<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2023 Workiva-->
<!--r:1fe3b42f-e8c6-4aa6-8f43-71c455cab7fc,g:8c1b1d62-69eb-4bfc-84d8-4a425fdf37b1-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="are-20230331.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedStatementsofOperations" xlink:type="extended" id="i9e1f49e7447c4cee82103140f281712a_ConsolidatedStatementsofOperations">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_0344c6bd-1fbc-4105-839e-2ba5b71caed1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_0344c6bd-1fbc-4105-839e-2ba5b71caed1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_cb5c5380-373f-4d87-9628-fad6c527ed1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:to="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_cb5c5380-373f-4d87-9628-fad6c527ed1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_d3a47262-c6a2-42b8-8fae-556cc5010d75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_d3a47262-c6a2-42b8-8fae-556cc5010d75" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_2b45a73c-c3ca-46e2-8f71-fd9bfd4aa18f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:to="loc_us-gaap_InterestExpense_2b45a73c-c3ca-46e2-8f71-fd9bfd4aa18f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_8d3e1d5d-fd3e-4778-848e-3eea0fbbb257" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:to="loc_us-gaap_DepreciationAndAmortization_8d3e1d5d-fd3e-4778-848e-3eea0fbbb257" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_26968093-1a09-41f0-a360-2c617335be38" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_c48039b0-48f3-418f-8d64-3ebe38b8f823" xlink:to="loc_us-gaap_CostsAndExpenses_26968093-1a09-41f0-a360-2c617335be38" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_0ffed452-a95c-439e-8f1c-6faf8ca5b2fd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_0ffed452-a95c-439e-8f1c-6faf8ca5b2fd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_7d8407cc-266e-4e4e-807b-1982fba3a817" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_7d8407cc-266e-4e4e-807b-1982fba3a817" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_fc6d6cab-6507-439d-a144-0edeb72d1461" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_ProfitLoss_fc6d6cab-6507-439d-a144-0edeb72d1461" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_61ddc56b-c6b2-4260-a657-7abef0b92428" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_61ddc56b-c6b2-4260-a657-7abef0b92428" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a1ae18d4-a94b-4648-b557-f664c98301d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_NetIncomeLoss_a1ae18d4-a94b-4648-b557-f664c98301d9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted_d01acd7e-9bc2-4061-88c2-a830e7b9c29a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted_d01acd7e-9bc2-4061-88c2-a830e7b9c29a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_e57c9532-3cbd-4eb4-8565-53d3fd568bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_e57c9532-3cbd-4eb4-8565-53d3fd568bb9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_4bbaeda8-f742-4cf0-857b-21aed870e0e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_EarningsPerShareBasic_4bbaeda8-f742-4cf0-857b-21aed870e0e8" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_761f95dd-6ea2-4e29-9f17-a15c7ce516e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_EarningsPerShareDiluted_761f95dd-6ea2-4e29-9f17-a15c7ce516e1" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_14a2af37-9167-4d41-b850-e0320d1b3b9d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_664010f2-b26d-482b-a455-4eb52f04a2a4" xlink:to="loc_us-gaap_StatementTable_14a2af37-9167-4d41-b850-e0320d1b3b9d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_d5b5aa4e-7770-477f-8cbb-1d9357896fc2" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_14a2af37-9167-4d41-b850-e0320d1b3b9d" xlink:to="loc_srt_ProductOrServiceAxis_d5b5aa4e-7770-477f-8cbb-1d9357896fc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d5b5aa4e-7770-477f-8cbb-1d9357896fc2_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_d5b5aa4e-7770-477f-8cbb-1d9357896fc2" xlink:to="loc_srt_ProductsAndServicesDomain_d5b5aa4e-7770-477f-8cbb-1d9357896fc2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_7fac26ed-4024-45fd-ad0d-cf773b8a4d7b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_d5b5aa4e-7770-477f-8cbb-1d9357896fc2" xlink:to="loc_srt_ProductsAndServicesDomain_7fac26ed-4024-45fd-ad0d-cf773b8a4d7b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_96f35fd5-2a5f-439e-b281-53821be362f9" xlink:href="are-20230331.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7fac26ed-4024-45fd-ad0d-cf773b8a4d7b" xlink:to="loc_are_IncomefromrentalsMember_96f35fd5-2a5f-439e-b281-53821be362f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_de92470a-b997-4f66-844e-1fae914ab9e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_7fac26ed-4024-45fd-ad0d-cf773b8a4d7b" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_de92470a-b997-4f66-844e-1fae914ab9e0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests" xlink:type="simple" xlink:href="are-20230331.xsd#ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests" xlink:type="extended" id="id602eebfde4646de910494a66f7adc7c_ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_e57bcdc9-5942-4c5e-8bd2-f90ab0f113db" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e57bcdc9-5942-4c5e-8bd2-f90ab0f113db" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_28b09da5-bb43-4f6e-a14e-0a6e9ae9f211" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_28b09da5-bb43-4f6e-a14e-0a6e9ae9f211" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_f18cc3ae-074b-48a6-8f0f-37fe8afd625f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_f18cc3ae-074b-48a6-8f0f-37fe8afd625f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_c4416d99-4a06-4f1d-8a7c-871da43bfc13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_c4416d99-4a06-4f1d-8a7c-871da43bfc13" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest_350d382f-4445-4d6e-a819-3e21a3bbda3a" xlink:href="are-20230331.xsd#are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest_350d382f-4445-4d6e-a819-3e21a3bbda3a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_a56af5d7-44da-4f7d-89ab-6841bc87ff75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_a56af5d7-44da-4f7d-89ab-6841bc87ff75" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_82f9da29-bf03-4340-a10c-6eb7ad579779" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_82f9da29-bf03-4340-a10c-6eb7ad579779" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_47ea97a7-e2a5-41ac-b1bf-1b7fc1dc0e72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_47ea97a7-e2a5-41ac-b1bf-1b7fc1dc0e72" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_42fc4a21-26e5-4ad3-817a-5bf04d646328" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueNewIssues_42fc4a21-26e5-4ad3-817a-5bf04d646328" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_bbdf1d98-00cf-4d3a-a567-0dfcf74f3e51" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_bbdf1d98-00cf-4d3a-a567-0dfcf74f3e51" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5ad4cc41-eaea-4b59-9627-46867394012e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5ad4cc41-eaea-4b59-9627-46867394012e" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_bf769798-9271-42fb-aeda-1910fbd773c6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_bf769798-9271-42fb-aeda-1910fbd773c6" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_45d1af5b-d8fd-4b68-a079-76f99a0e346c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_45d1af5b-d8fd-4b68-a079-76f99a0e346c" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_bc974784-2a87-4597-951e-9bb2c3d5d077" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_DividendsCommonStockCash_bc974784-2a87-4597-951e-9bb2c3d5d077" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_681a5765-612e-49ba-9475-1429d03e0235" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e3e3301d-0321-466c-8e2f-5ffa2989ce88" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_681a5765-612e-49ba-9475-1429d03e0235" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_7a98c378-b1c2-497b-b8ed-dc4b0545a81c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_abedd2d3-dd0f-434e-8486-1f332605315d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_e57bcdc9-5942-4c5e-8bd2-f90ab0f113db" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_d95dccfa-0210-4f25-b2ae-6b2111f86032" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_d95dccfa-0210-4f25-b2ae-6b2111f86032" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityNetIncome_5e2ddd63-bc34-4e15-b9b1-e863ca4c63c0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:to="loc_us-gaap_TemporaryEquityNetIncome_5e2ddd63-bc34-4e15-b9b1-e863ca4c63c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Temporaryequitycontributionfromnoncontrollinginterests_b8b33678-870c-4a2e-8db0-49f1f42dea70" xlink:href="are-20230331.xsd#are_Temporaryequitycontributionfromnoncontrollinginterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:to="loc_are_Temporaryequitycontributionfromnoncontrollinginterests_b8b33678-870c-4a2e-8db0-49f1f42dea70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest_cb694f7b-6a02-467a-a11e-071b8b554de2" xlink:href="are-20230331.xsd#are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_10e964de-2f4c-4d0c-b43f-31f2ca66eda9" xlink:to="loc_are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest_cb694f7b-6a02-467a-a11e-071b8b554de2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_564d79fb-ac69-4b2f-b798-e6f15ebda8b1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_a86810ec-ee9a-4d7f-afc3-cc71de5b032d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_e57bcdc9-5942-4c5e-8bd2-f90ab0f113db" xlink:to="loc_us-gaap_StatementTable_a86810ec-ee9a-4d7f-afc3-cc71de5b032d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_a86810ec-ee9a-4d7f-afc3-cc71de5b032d" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16" xlink:to="loc_us-gaap_EquityComponentDomain_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_93baae9b-389e-4c8b-bc1b-c6b2e4b3fe16" xlink:to="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_4856a929-e59d-4243-b6f9-e1e691621bee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_us-gaap_CommonStockMember_4856a929-e59d-4243-b6f9-e1e691621bee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_4e32804c-835d-4695-ab94-c180cb7dc7d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_4e32804c-835d-4695-ab94-c180cb7dc7d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_78a89e89-35de-4216-9c35-873931228d30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_us-gaap_RetainedEarningsMember_78a89e89-35de-4216-9c35-873931228d30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_45ad6222-7acc-4664-9185-b2ea0ed7275d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_45ad6222-7acc-4664-9185-b2ea0ed7275d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_81876ac4-d6b8-4b2b-aecb-95ae70bd8d78" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_us-gaap_NoncontrollingInterestMember_81876ac4-d6b8-4b2b-aecb-95ae70bd8d78" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RedeemableNoncontrollingInterestsMember_c795ee34-0c10-4f45-b1cb-a63de6ea8606" xlink:href="are-20230331.xsd#are_RedeemableNoncontrollingInterestsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_29187b18-891a-48cd-b021-67fba0ff730d" xlink:to="loc_are_RedeemableNoncontrollingInterestsMember_c795ee34-0c10-4f45-b1cb-a63de6ea8606" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SummaryofsignificantaccountingpoliciesDetails" xlink:type="simple" xlink:href="are-20230331.xsd#SummaryofsignificantaccountingpoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SummaryofsignificantaccountingpoliciesDetails" xlink:type="extended" id="i439b31fa93bb453cae7ff97dff10e01e_SummaryofsignificantaccountingpoliciesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_9961ce39-6e43-47d8-a17a-866cbc5415f1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_9961ce39-6e43-47d8-a17a-866cbc5415f1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MaximumExpectedPeriodOfSaleOfProperty_bb285f08-8b31-4e82-9c73-b9d3f0edcc32" xlink:href="are-20230331.xsd#are_MaximumExpectedPeriodOfSaleOfProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_MaximumExpectedPeriodOfSaleOfProperty_bb285f08-8b31-4e82-9c73-b9d3f0edcc32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_b189cb43-4bc7-488a-9ce1-ff61b22b9d14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_b189cb43-4bc7-488a-9ce1-ff61b22b9d14" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CostMethodInvestmentOwnershipPercentage_e1c841ba-2e52-42cf-98e3-91ee8c1dd0e7" xlink:href="are-20230331.xsd#are_CostMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_CostMethodInvestmentOwnershipPercentage_e1c841ba-2e52-42cf-98e3-91ee8c1dd0e7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Percentageoftotalrevenues_c175b104-a530-4b6a-8e64-7d2811299087" xlink:href="are-20230331.xsd#are_Percentageoftotalrevenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_Percentageoftotalrevenues_c175b104-a530-4b6a-8e64-7d2811299087" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ContractWithCustomerAssetAdjustmentForAllowanceForCreditLoss_f51c2c67-e23c-4f82-a9a4-14fa87728cae" xlink:href="are-20230331.xsd#are_ContractWithCustomerAssetAdjustmentForAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_ContractWithCustomerAssetAdjustmentForAllowanceForCreditLoss_f51c2c67-e23c-4f82-a9a4-14fa87728cae" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_e80e8e40-0275-42a9-afe7-0d02e836b5c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_e80e8e40-0275-42a9-afe7-0d02e836b5c4" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MinimumPercentageOfTaxableIncomeToBeDistributed_13a9fce2-2703-4582-8e75-7cdb3ad8b9fb" xlink:href="are-20230331.xsd#are_MinimumPercentageOfTaxableIncomeToBeDistributed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_MinimumPercentageOfTaxableIncomeToBeDistributed_13a9fce2-2703-4582-8e75-7cdb3ad8b9fb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PercentOfTaxableIncomeGenerallyDistributedAsDividend_9ee1c00b-9344-4b23-88f1-509de13edf8f" xlink:href="are-20230331.xsd#are_PercentOfTaxableIncomeGenerallyDistributedAsDividend"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_are_PercentOfTaxableIncomeGenerallyDistributedAsDividend_9ee1c00b-9344-4b23-88f1-509de13edf8f" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_0dab62c2-0773-4a3f-933f-1528f736e8fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_0dab62c2-0773-4a3f-933f-1528f736e8fb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_9b62e595-c696-4e92-80b8-3e0fe26d2356" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_9b62e595-c696-4e92-80b8-3e0fe26d2356" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseIncome_19bdd977-6bc3-46bc-8fb9-97e14da2aff2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:to="loc_us-gaap_LeaseIncome_19bdd977-6bc3-46bc-8fb9-97e14da2aff2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_9da88b3c-ee64-4178-82a0-cb2b8a215050" xlink:href="are-20230331.xsd#are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:to="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_9da88b3c-ee64-4178-82a0-cb2b8a215050" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_a27c05d7-f2bd-450d-8cca-1c6be41ac0ca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_2cb04546-4da4-4ff3-8256-3854b1d864a4" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_a27c05d7-f2bd-450d-8cca-1c6be41ac0ca" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_92b2b247-1d74-4eee-a1b8-1b16f39b728e" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:to="loc_srt_ProductOrServiceAxis_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95" xlink:to="loc_srt_ProductsAndServicesDomain_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_235a7c16-15c8-4d53-b27b-8a5cdd8f6259" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_9d828d2e-8f6e-4582-bcc8-ae2d359f9a95" xlink:to="loc_srt_ProductsAndServicesDomain_235a7c16-15c8-4d53-b27b-8a5cdd8f6259" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_192277bf-6a0b-4c8c-a802-7bdeeb7c690e" xlink:href="are-20230331.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_235a7c16-15c8-4d53-b27b-8a5cdd8f6259" xlink:to="loc_are_IncomefromrentalsMember_192277bf-6a0b-4c8c-a802-7bdeeb7c690e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_f6447c8d-be21-4a6b-9136-bf97bb82b788" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_235a7c16-15c8-4d53-b27b-8a5cdd8f6259" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_f6447c8d-be21-4a6b-9136-bf97bb82b788" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RevenuessubjecttootheraccountingguidanceMember_75ca5c38-e597-479a-8c7b-a4c65e25fa72" xlink:href="are-20230331.xsd#are_RevenuessubjecttootheraccountingguidanceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_235a7c16-15c8-4d53-b27b-8a5cdd8f6259" xlink:to="loc_are_RevenuessubjecttootheraccountingguidanceMember_75ca5c38-e597-479a-8c7b-a4c65e25fa72" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:to="loc_srt_StatementGeographicalAxis_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8" xlink:to="loc_srt_SegmentGeographicalDomain_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_be9ee4b4-ca7f-46ae-a006-3f82788ac730" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_e2c9b62d-1a4a-4bf8-a8bd-029efc75ece8" xlink:to="loc_srt_SegmentGeographicalDomain_be9ee4b4-ca7f-46ae-a006-3f82788ac730" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_d609bbd6-4768-46a4-976f-d36e410698ec" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_be9ee4b4-ca7f-46ae-a006-3f82788ac730" xlink:to="loc_country_CA_d609bbd6-4768-46a4-976f-d36e410698ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CN_37e17173-9d53-407a-9a3c-0aaeb9f87fd4" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_CN"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_be9ee4b4-ca7f-46ae-a006-3f82788ac730" xlink:to="loc_country_CN_37e17173-9d53-407a-9a3c-0aaeb9f87fd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71fa9439-83ac-4033-8937-1c58ea3f4401" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71fa9439-83ac-4033-8937-1c58ea3f4401" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_71fa9439-83ac-4033-8937-1c58ea3f4401_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71fa9439-83ac-4033-8937-1c58ea3f4401" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_71fa9439-83ac-4033-8937-1c58ea3f4401_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_04579fad-c4ae-4e22-9032-63561ccf64f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_71fa9439-83ac-4033-8937-1c58ea3f4401" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_04579fad-c4ae-4e22-9032-63561ccf64f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandImprovementsMember_3c242eba-1ad6-48a9-bad9-46b6fc287d47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LandImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_04579fad-c4ae-4e22-9032-63561ccf64f5" xlink:to="loc_us-gaap_LandImprovementsMember_3c242eba-1ad6-48a9-bad9-46b6fc287d47" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_1d7a203e-53de-4fd9-b7a5-696390c6322f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_04579fad-c4ae-4e22-9032-63561ccf64f5" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_1d7a203e-53de-4fd9-b7a5-696390c6322f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_98d45b65-8b67-41e6-b997-5b13229f2181" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:to="loc_srt_RangeAxis_98d45b65-8b67-41e6-b997-5b13229f2181" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_98d45b65-8b67-41e6-b997-5b13229f2181_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_98d45b65-8b67-41e6-b997-5b13229f2181" xlink:to="loc_srt_RangeMember_98d45b65-8b67-41e6-b997-5b13229f2181_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_621a376d-81b4-4ac5-a152-7b52c392e34a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_98d45b65-8b67-41e6-b997-5b13229f2181" xlink:to="loc_srt_RangeMember_621a376d-81b4-4ac5-a152-7b52c392e34a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_d1bdefe8-76e7-4ed8-bfc4-c73c98a75b50" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_621a376d-81b4-4ac5-a152-7b52c392e34a" xlink:to="loc_srt_MaximumMember_d1bdefe8-76e7-4ed8-bfc4-c73c98a75b50" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_85ba7e91-7a74-42ec-9899-59c72e7fedf6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_80f0f827-73ed-43d7-adcc-bde0d2c0ab8f" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_85ba7e91-7a74-42ec-9899-59c72e7fedf6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_85ba7e91-7a74-42ec-9899-59c72e7fedf6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_85ba7e91-7a74-42ec-9899-59c72e7fedf6" xlink:to="loc_us-gaap_TypeOfAdoptionMember_85ba7e91-7a74-42ec-9899-59c72e7fedf6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_16a2f535-1dfa-42a7-bb9c-687cd2f26879" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_85ba7e91-7a74-42ec-9899-59c72e7fedf6" xlink:to="loc_us-gaap_TypeOfAdoptionMember_16a2f535-1dfa-42a7-bb9c-687cd2f26879" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdate201409Member_8bdaf87a-da77-4798-9590-d456272fd49a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountingStandardsUpdate201409Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_16a2f535-1dfa-42a7-bb9c-687cd2f26879" xlink:to="loc_us-gaap_AccountingStandardsUpdate201409Member_8bdaf87a-da77-4798-9590-d456272fd49a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails" xlink:type="simple" xlink:href="are-20230331.xsd#InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails" xlink:type="extended" id="i15cf5435173f4e77a8a5c6f6ff9c9f94_InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Land_a91b06dc-ee12-4a1c-bab3-d14e90a4e7c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Land"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_Land_a91b06dc-ee12-4a1c-bab3-d14e90a4e7c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentBuildingAndBuildingImprovements_e3bcc791-a693-4731-b932-dbbffd18bdbe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentBuildingAndBuildingImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_InvestmentBuildingAndBuildingImprovements_e3bcc791-a693-4731-b932-dbbffd18bdbe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ImprovementsOthers_98b20187-a909-4d79-a668-0f5e2c324b5c" xlink:href="are-20230331.xsd#are_ImprovementsOthers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_are_ImprovementsOthers_98b20187-a909-4d79-a668-0f5e2c324b5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RentalProperties_df4aa0a7-c2bd-44f8-9d10-cb086cb95e7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RentalProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_RentalProperties_df4aa0a7-c2bd-44f8-9d10-cb086cb95e7b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopmentInProcess_f6509bc8-da2b-4e1d-b218-ef2772a76a0f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DevelopmentInProcess"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_DevelopmentInProcess_f6509bc8-da2b-4e1d-b218-ef2772a76a0f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost_93965c8c-0d16-4596-9e39-085bd18951cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAtCost_93965c8c-0d16-4596-9e39-085bd18951cd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_12d5c27e-200e-4dae-a600-c3d8b0c51187" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_12d5c27e-200e-4dae-a600-c3d8b0c51187" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_4871472d-db3e-4059-b475-62e0eb602171" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_4871472d-db3e-4059-b475-62e0eb602171" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTable_b402baa0-4788-462e-989a-921913af7e7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RealEstateLineItems_ba60e59f-588f-41a8-8850-48b07861e18f" xlink:to="loc_us-gaap_RealEstateTable_b402baa0-4788-462e-989a-921913af7e7f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_f5ad0d25-f2d4-4377-ba22-b4e80e929197" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_b402baa0-4788-462e-989a-921913af7e7f" xlink:to="loc_srt_StatementGeographicalAxis_f5ad0d25-f2d4-4377-ba22-b4e80e929197" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_f5ad0d25-f2d4-4377-ba22-b4e80e929197_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_f5ad0d25-f2d4-4377-ba22-b4e80e929197" xlink:to="loc_srt_SegmentGeographicalDomain_f5ad0d25-f2d4-4377-ba22-b4e80e929197_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_1cc2b3bf-a5a9-4e26-9b48-967af0acb552" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_f5ad0d25-f2d4-4377-ba22-b4e80e929197" xlink:to="loc_srt_SegmentGeographicalDomain_1cc2b3bf-a5a9-4e26-9b48-967af0acb552" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_a78d6f8c-66c1-4fde-8fdf-8a35de422599" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_1cc2b3bf-a5a9-4e26-9b48-967af0acb552" xlink:to="loc_srt_NorthAmericaMember_a78d6f8c-66c1-4fde-8fdf-8a35de422599" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaMember_d92ca781-3d20-4fc3-ae29-1a2832ab23dc" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_AsiaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_1cc2b3bf-a5a9-4e26-9b48-967af0acb552" xlink:to="loc_srt_AsiaMember_d92ca781-3d20-4fc3-ae29-1a2832ab23dc" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsinrealestateAcquisitionDetails" xlink:type="simple" xlink:href="are-20230331.xsd#InvestmentsinrealestateAcquisitionDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsinrealestateAcquisitionDetails" xlink:type="extended" id="if925a2f67ac14ca398ca74ddf2305683_InvestmentsinrealestateAcquisitionDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfRealEstatePropertiesAcquired_9dc69e9b-6fcd-4bb1-b99f-8c6d461957af" xlink:href="are-20230331.xsd#are_NumberOfRealEstatePropertiesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_are_NumberOfRealEstatePropertiesAcquired_9dc69e9b-6fcd-4bb1-b99f-8c6d461957af" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_f4927c45-a745-4232-9501-2a207c0d0f3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_f4927c45-a745-4232-9501-2a207c0d0f3a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireRealEstate_9a1524fb-e09a-4710-ac84-cf47f1b44701" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_us-gaap_PaymentsToAcquireRealEstate_9a1524fb-e09a-4710-ac84-cf47f1b44701" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FiniteLivedIntangibleAssetsAcquiredThroughAcquisitions_c2e51785-acc6-4082-9007-b890ec93f773" xlink:href="are-20230331.xsd#are_FiniteLivedIntangibleAssetsAcquiredThroughAcquisitions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_are_FiniteLivedIntangibleAssetsAcquiredThroughAcquisitions_c2e51785-acc6-4082-9007-b890ec93f773" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BelowMarketLeaseGross_9937d4bd-988c-4825-9d84-0ac52cb173b2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BelowMarketLeaseGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_us-gaap_BelowMarketLeaseGross_9937d4bd-988c-4825-9d84-0ac52cb173b2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Weightedaverageremainingamortizationperiodacquiredinplaceandbelowmarketleases_3fdae1d5-8457-4846-9b60-b621b2904f12" xlink:href="are-20230331.xsd#are_Weightedaverageremainingamortizationperiodacquiredinplaceandbelowmarketleases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_are_Weightedaverageremainingamortizationperiodacquiredinplaceandbelowmarketleases_3fdae1d5-8457-4846-9b60-b621b2904f12" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTable_280060cc-20b4-4750-b0c5-fcc312b74c8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RealEstateLineItems_0f366335-15be-4949-ade1-f421604683d9" xlink:to="loc_us-gaap_RealEstateTable_280060cc-20b4-4750-b0c5-fcc312b74c8c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_3495fb29-e29c-472f-a486-d35203f69539" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_280060cc-20b4-4750-b0c5-fcc312b74c8c" xlink:to="loc_srt_StatementGeographicalAxis_3495fb29-e29c-472f-a486-d35203f69539" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_3495fb29-e29c-472f-a486-d35203f69539_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_3495fb29-e29c-472f-a486-d35203f69539" xlink:to="loc_srt_SegmentGeographicalDomain_3495fb29-e29c-472f-a486-d35203f69539_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_cd485410-cfdc-4f5e-a445-9dc05bb766b5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_3495fb29-e29c-472f-a486-d35203f69539" xlink:to="loc_srt_SegmentGeographicalDomain_cd485410-cfdc-4f5e-a445-9dc05bb766b5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_4d22153c-1b9e-47c7-a0d8-4ee36c682d9b" xlink:href="https://xbrl.sec.gov/country/2022/country-2022.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_cd485410-cfdc-4f5e-a445-9dc05bb766b5" xlink:to="loc_country_CA_4d22153c-1b9e-47c7-a0d8-4ee36c682d9b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OthermarketsMember_0d083b4d-d6c9-4663-b823-29601e99245b" xlink:href="are-20230331.xsd#are_OthermarketsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_cd485410-cfdc-4f5e-a445-9dc05bb766b5" xlink:to="loc_are_OthermarketsMember_0d083b4d-d6c9-4663-b823-29601e99245b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_f06624b8-b2fb-4e51-8814-48a98f0acb43" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_cd485410-cfdc-4f5e-a445-9dc05bb766b5" xlink:to="loc_srt_NorthAmericaMember_f06624b8-b2fb-4e51-8814-48a98f0acb43" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeAxis_a02512ef-94a2-48d2-b4ae-81c7a7f773c7" xlink:href="are-20230331.xsd#are_PropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_280060cc-20b4-4750-b0c5-fcc312b74c8c" xlink:to="loc_are_PropertyTypeAxis_a02512ef-94a2-48d2-b4ae-81c7a7f773c7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_a02512ef-94a2-48d2-b4ae-81c7a7f773c7_default" xlink:href="are-20230331.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PropertyTypeAxis_a02512ef-94a2-48d2-b4ae-81c7a7f773c7" xlink:to="loc_are_PropertyTypeDomain_a02512ef-94a2-48d2-b4ae-81c7a7f773c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:href="are-20230331.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PropertyTypeAxis_a02512ef-94a2-48d2-b4ae-81c7a7f773c7" xlink:to="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FuturedevelopmentprojectsMember_33f076b9-f6bb-457b-a308-bc97131fcc12" xlink:href="are-20230331.xsd#are_FuturedevelopmentprojectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:to="loc_are_FuturedevelopmentprojectsMember_33f076b9-f6bb-457b-a308-bc97131fcc12" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ActiveDevelopmentRedevelopmentMember_0fb617a3-2cc1-4b9e-bd8f-e7725ebab1b9" xlink:href="are-20230331.xsd#are_ActiveDevelopmentRedevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:to="loc_are_ActiveDevelopmentRedevelopmentMember_0fb617a3-2cc1-4b9e-bd8f-e7725ebab1b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingwithfuturedevelopmentandredevelopmentMember_8ebc435f-88d3-4601-9215-b4412b28308d" xlink:href="are-20230331.xsd#are_OperatingwithfuturedevelopmentandredevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:to="loc_are_OperatingwithfuturedevelopmentandredevelopmentMember_8ebc435f-88d3-4601-9215-b4412b28308d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingpropertiesMember_e43babb3-488f-4b14-b1b9-267997ecc1b9" xlink:href="are-20230331.xsd#are_OperatingpropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_bc0f9c36-9f44-496a-a072-87569a265e87" xlink:to="loc_are_OperatingpropertiesMember_e43babb3-488f-4b14-b1b9-267997ecc1b9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_efcd1db5-5734-4f70-8784-481db03d2884" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_280060cc-20b4-4750-b0c5-fcc312b74c8c" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_efcd1db5-5734-4f70-8784-481db03d2884" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_efcd1db5-5734-4f70-8784-481db03d2884_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_efcd1db5-5734-4f70-8784-481db03d2884" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_efcd1db5-5734-4f70-8784-481db03d2884_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fd9fe07c-2f45-43a5-ad8d-b67487ca0d47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_efcd1db5-5734-4f70-8784-481db03d2884" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fd9fe07c-2f45-43a5-ad8d-b67487ca0d47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAcquiredInPlaceMember_573645e7-accd-4bd2-8107-74933b714655" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAcquiredInPlaceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fd9fe07c-2f45-43a5-ad8d-b67487ca0d47" xlink:to="loc_us-gaap_LeasesAcquiredInPlaceMember_573645e7-accd-4bd2-8107-74933b714655" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AboveandBelowMarketLeasesMember_88a03c65-18d0-400a-8cef-29b5374af872" xlink:href="are-20230331.xsd#are_AboveandBelowMarketLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_fd9fe07c-2f45-43a5-ad8d-b67487ca0d47" xlink:to="loc_are_AboveandBelowMarketLeasesMember_88a03c65-18d0-400a-8cef-29b5374af872" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresDetails" xlink:type="simple" xlink:href="are-20230331.xsd#ConsolidatedandunconsolidatedrealestatejointventuresDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresDetails" xlink:type="extended" id="i3cb38c93a9824cfda30387b8451eabfa_ConsolidatedandunconsolidatedrealestatejointventuresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_93723b55-5bcc-42bb-8df9-e5cda2262196" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_93723b55-5bcc-42bb-8df9-e5cda2262196" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_19c660fe-da09-4184-b0da-1e20cca7f389" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_19c660fe-da09-4184-b0da-1e20cca7f389" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_e4fb8899-47e1-478d-903d-9fedc52b7629" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_e4fb8899-47e1-478d-903d-9fedc52b7629" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_40c661bc-0dbc-4774-9a58-cfe89af82c04" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_40c661bc-0dbc-4774-9a58-cfe89af82c04" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireRealEstate_7588085f-8980-4e49-9821-b4b12b7b0871" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_PaymentsToAcquireRealEstate_7588085f-8980-4e49-9821-b4b12b7b0871" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TotalValueOfAssetsAcquired_78b79926-3504-4676-b470-9ec96ee9f8a7" xlink:href="are-20230331.xsd#are_TotalValueOfAssetsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_are_TotalValueOfAssetsAcquired_78b79926-3504-4676-b470-9ec96ee9f8a7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1_ffff6fb1-289e-493f-9631-8a649ee8b2cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1_ffff6fb1-289e-493f-9631-8a649ee8b2cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Temporaryequitycontributionfromnoncontrollinginterests_4aea89c8-baa6-4d25-8bbd-ea17659579cc" xlink:href="are-20230331.xsd#are_Temporaryequitycontributionfromnoncontrollinginterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_are_Temporaryequitycontributionfromnoncontrollinginterests_4aea89c8-baa6-4d25-8bbd-ea17659579cc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_f0527867-2ecd-4d9f-8bee-248bd4cc9a8e" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_eb996abd-4a43-4f79-927b-5e76fa3274f5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_eb996abd-4a43-4f79-927b-5e76fa3274f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_eb996abd-4a43-4f79-927b-5e76fa3274f5_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_eb996abd-4a43-4f79-927b-5e76fa3274f5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_eb996abd-4a43-4f79-927b-5e76fa3274f5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_eb996abd-4a43-4f79-927b-5e76fa3274f5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A50And60BinneyStreetMember_31d7bc1c-935b-492e-b761-2e8440a691fc" xlink:href="are-20230331.xsd#are_A50And60BinneyStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A50And60BinneyStreetMember_31d7bc1c-935b-492e-b761-2e8440a691fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A75125BinneyStreetMember_c1801791-7413-4c32-8e33-0564cb9ba96d" xlink:href="are-20230331.xsd#are_A75125BinneyStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A75125BinneyStreetMember_c1801791-7413-4c32-8e33-0564cb9ba96d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A100And225BinneyStreetAnd300ThirdStreetMember_e5458a26-c87f-43de-846f-48361d862a1d" xlink:href="are-20230331.xsd#are_A100And225BinneyStreetAnd300ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A100And225BinneyStreetAnd300ThirdStreetMember_e5458a26-c87f-43de-846f-48361d862a1d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A99CoolidgeAvenueMember_9e32fc99-bc43-4c82-bf0b-fb81ad030a6c" xlink:href="are-20230331.xsd#are_A99CoolidgeAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A99CoolidgeAvenueMember_9e32fc99-bc43-4c82-bf0b-fb81ad030a6c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A15NeccoStreetMember_1318717e-9c9b-49a5-87bd-17265d0623e0" xlink:href="are-20230331.xsd#are_A15NeccoStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A15NeccoStreetMember_1318717e-9c9b-49a5-87bd-17265d0623e0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherGreaterBostonMember_5c8da4cd-c1fd-48a2-95bb-7d8b3dcc4587" xlink:href="are-20230331.xsd#are_OtherGreaterBostonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_OtherGreaterBostonMember_5c8da4cd-c1fd-48a2-95bb-7d8b3dcc4587" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaCenterForScienceAndTechnologyMissionBayMember_e9e97d02-75f5-4bd6-a644-726085912e4f" xlink:href="are-20230331.xsd#are_AlexandriaCenterForScienceAndTechnologyMissionBayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_AlexandriaCenterForScienceAndTechnologyMissionBayMember_e9e97d02-75f5-4bd6-a644-726085912e4f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1450OwensStreetMember_42bb1654-0b81-4cfb-a699-b91371b5fbdb" xlink:href="are-20230331.xsd#are_A1450OwensStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A1450OwensStreetMember_42bb1654-0b81-4cfb-a699-b91371b5fbdb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A601611651681685And701GatewayBoulevardMember_28b93ec6-c88b-472b-ac49-0868ddd09ed5" xlink:href="are-20230331.xsd#are_A601611651681685And701GatewayBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A601611651681685And701GatewayBoulevardMember_28b93ec6-c88b-472b-ac49-0868ddd09ed5" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A751GatewayBoulevardMember_fcf827c5-d6dc-4db3-b8fe-afe7b0f6d5f6" xlink:href="are-20230331.xsd#are_A751GatewayBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A751GatewayBoulevardMember_fcf827c5-d6dc-4db3-b8fe-afe7b0f6d5f6" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A213EastGrandAvenueMember_42496230-603a-4690-8aa5-c5c0943d6609" xlink:href="are-20230331.xsd#are_A213EastGrandAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A213EastGrandAvenueMember_42496230-603a-4690-8aa5-c5c0943d6609" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A500ForbesBoulevardMember_80f07123-3195-4ab0-9a7b-fda1fbda8153" xlink:href="are-20230331.xsd#are_A500ForbesBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A500ForbesBoulevardMember_80f07123-3195-4ab0-9a7b-fda1fbda8153" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaCenterForLifeScienceMillbraeMember_f0d6da3d-a13b-4863-9350-29b5387f388e" xlink:href="are-20230331.xsd#are_AlexandriaCenterForLifeScienceMillbraeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_AlexandriaCenterForLifeScienceMillbraeMember_f0d6da3d-a13b-4863-9350-29b5387f388e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3215MerryfieldRowMember_abf9b340-992c-4384-bf45-87f1ee38d86d" xlink:href="are-20230331.xsd#are_A3215MerryfieldRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A3215MerryfieldRowMember_abf9b340-992c-4384-bf45-87f1ee38d86d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CampusPointByAlexandriaMember_d5fb36f6-e9f2-49a5-bcb6-ea475e9ee373" xlink:href="are-20230331.xsd#are_CampusPointByAlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_CampusPointByAlexandriaMember_d5fb36f6-e9f2-49a5-bcb6-ea475e9ee373" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5200IlluminaWayMember_f6694ed5-ac10-4f80-ab9f-741fcebd2c1a" xlink:href="are-20230331.xsd#are_A5200IlluminaWayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A5200IlluminaWayMember_f6694ed5-ac10-4f80-ab9f-741fcebd2c1a" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A9625TowneCentreDriveMember_601de78c-4f0d-489b-b97d-b99c7a2394a4" xlink:href="are-20230331.xsd#are_A9625TowneCentreDriveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A9625TowneCentreDriveMember_601de78c-4f0d-489b-b97d-b99c7a2394a4" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SDTechbyAlexandriaMember_e58cbdda-21fa-45b8-9374-56679c12627c" xlink:href="are-20230331.xsd#are_SDTechbyAlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_SDTechbyAlexandriaMember_e58cbdda-21fa-45b8-9374-56679c12627c" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PacificTechnologyParkMember_cd49bab2-be70-47a3-8387-7ca69aab0200" xlink:href="are-20230331.xsd#are_PacificTechnologyParkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_PacificTechnologyParkMember_cd49bab2-be70-47a3-8387-7ca69aab0200" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SummersRidgeScienceParkMember_7c6d5f6b-4a43-40bd-84ab-37557e52ae7b" xlink:href="are-20230331.xsd#are_SummersRidgeScienceParkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_SummersRidgeScienceParkMember_7c6d5f6b-4a43-40bd-84ab-37557e52ae7b" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1201And1208EastlakeAvenueEastAnd199EastBlaineStreetMember_c61a292a-7a68-4f9c-9092-54b62b949665" xlink:href="are-20230331.xsd#are_A1201And1208EastlakeAvenueEastAnd199EastBlaineStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A1201And1208EastlakeAvenueEastAnd199EastBlaineStreetMember_c61a292a-7a68-4f9c-9092-54b62b949665" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A400DexterAvenueNorthMember_ac48da4f-cdb2-43ef-87c8-b6f95b0fc88e" xlink:href="are-20230331.xsd#are_A400DexterAvenueNorthMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A400DexterAvenueNorthMember_ac48da4f-cdb2-43ef-87c8-b6f95b0fc88e" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A800MercerStreetMember_5aa431fb-4e52-47a4-9938-cde224dc75fd" xlink:href="are-20230331.xsd#are_A800MercerStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_9a406a1d-0664-4304-badc-a832e8a72c0e" xlink:to="loc_are_A800MercerStreetMember_5aa431fb-4e52-47a4-9938-cde224dc75fd" xlink:type="arc" order="22"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eff333b5-51f4-4e5a-93f1-70f518097b0d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eff333b5-51f4-4e5a-93f1-70f518097b0d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_eff333b5-51f4-4e5a-93f1-70f518097b0d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eff333b5-51f4-4e5a-93f1-70f518097b0d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_eff333b5-51f4-4e5a-93f1-70f518097b0d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_eff333b5-51f4-4e5a-93f1-70f518097b0d" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1655and1715ThirdStreetMember_1c950d52-1369-4ade-ba92-634280d75fc7" xlink:href="are-20230331.xsd#are_A1655and1715ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:to="loc_are_A1655and1715ThirdStreetMember_1c950d52-1369-4ade-ba92-634280d75fc7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A14011413ResearchBoulevardMember_5434ceec-9c7f-4f0c-9a94-90c0644d2bb7" xlink:href="are-20230331.xsd#are_A14011413ResearchBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:to="loc_are_A14011413ResearchBoulevardMember_5434ceec-9c7f-4f0c-9a94-90c0644d2bb7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1450ResearchBoulevardMember_0a9f81af-3cb7-4b88-aac7-71b0da4f5b8b" xlink:href="are-20230331.xsd#are_A1450ResearchBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:to="loc_are_A1450ResearchBoulevardMember_0a9f81af-3cb7-4b88-aac7-71b0da4f5b8b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A101WestDickmanStreetMember_580a6e2e-7b42-4dfd-8987-b15d44f9916f" xlink:href="are-20230331.xsd#are_A101WestDickmanStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_8c7f00ac-8c26-45e2-abef-cb8ff0ac3b68" xlink:to="loc_are_A101WestDickmanStreetMember_580a6e2e-7b42-4dfd-8987-b15d44f9916f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_402e3dd9-6b76-419f-8ad8-903dc190d55f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:to="loc_srt_OwnershipAxis_402e3dd9-6b76-419f-8ad8-903dc190d55f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_402e3dd9-6b76-419f-8ad8-903dc190d55f_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_402e3dd9-6b76-419f-8ad8-903dc190d55f" xlink:to="loc_srt_OwnershipDomain_402e3dd9-6b76-419f-8ad8-903dc190d55f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_967b372a-5f3e-43fa-a637-f6b165303ca9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_402e3dd9-6b76-419f-8ad8-903dc190d55f" xlink:to="loc_srt_OwnershipDomain_967b372a-5f3e-43fa-a637-f6b165303ca9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaMember_c5a655d4-c055-41d4-93cc-a09e58f5a90e" xlink:href="are-20230331.xsd#are_AlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_967b372a-5f3e-43fa-a637-f6b165303ca9" xlink:to="loc_are_AlexandriaMember_c5a655d4-c055-41d4-93cc-a09e58f5a90e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c6b891e5-4b51-4a40-bff3-dde6736b5456" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c6b891e5-4b51-4a40-bff3-dde6736b5456" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c6b891e5-4b51-4a40-bff3-dde6736b5456_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c6b891e5-4b51-4a40-bff3-dde6736b5456" xlink:to="loc_us-gaap_EquityComponentDomain_c6b891e5-4b51-4a40-bff3-dde6736b5456_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_4bfa6dbe-9441-461e-80cb-8d481beff8ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c6b891e5-4b51-4a40-bff3-dde6736b5456" xlink:to="loc_us-gaap_EquityComponentDomain_4bfa6dbe-9441-461e-80cb-8d481beff8ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_3756170a-d6dd-42a5-acf1-2a108c9705ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4bfa6dbe-9441-461e-80cb-8d481beff8ee" xlink:to="loc_us-gaap_NoncontrollingInterestMember_3756170a-d6dd-42a5-acf1-2a108c9705ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RedeemableNoncontrollingInterestsMember_9cb124f9-718b-48d9-95ca-1e5b90089867" xlink:href="are-20230331.xsd#are_RedeemableNoncontrollingInterestsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4bfa6dbe-9441-461e-80cb-8d481beff8ee" xlink:to="loc_are_RedeemableNoncontrollingInterestsMember_9cb124f9-718b-48d9-95ca-1e5b90089867" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeAxis_4d1ac3dc-6349-423e-bdf4-cc147732a4e3" xlink:href="are-20230331.xsd#are_PropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_46e058d7-7e7e-46ae-a7c9-8fd23d0df8d1" xlink:to="loc_are_PropertyTypeAxis_4d1ac3dc-6349-423e-bdf4-cc147732a4e3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_4d1ac3dc-6349-423e-bdf4-cc147732a4e3_default" xlink:href="are-20230331.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PropertyTypeAxis_4d1ac3dc-6349-423e-bdf4-cc147732a4e3" xlink:to="loc_are_PropertyTypeDomain_4d1ac3dc-6349-423e-bdf4-cc147732a4e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_abd7950f-354d-403d-8466-db0abe4f157e" xlink:href="are-20230331.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PropertyTypeAxis_4d1ac3dc-6349-423e-bdf4-cc147732a4e3" xlink:to="loc_are_PropertyTypeDomain_abd7950f-354d-403d-8466-db0abe4f157e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FuturedevelopmentprojectsMember_ae7c2d1d-ccd8-43b7-93fa-b60ccc97ca93" xlink:href="are-20230331.xsd#are_FuturedevelopmentprojectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_abd7950f-354d-403d-8466-db0abe4f157e" xlink:to="loc_are_FuturedevelopmentprojectsMember_ae7c2d1d-ccd8-43b7-93fa-b60ccc97ca93" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DevelopmentEntitlementsAcquiredMember_cda63d49-1402-4a72-8cdd-102f4591d54f" xlink:href="are-20230331.xsd#are_DevelopmentEntitlementsAcquiredMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_abd7950f-354d-403d-8466-db0abe4f157e" xlink:to="loc_are_DevelopmentEntitlementsAcquiredMember_cda63d49-1402-4a72-8cdd-102f4591d54f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails" xlink:type="simple" xlink:href="are-20230331.xsd#ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails" xlink:type="extended" id="ic2ff45ac67d2404fa30e21d9bfc5fca3_ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_1837daa9-77ee-4ed3-989f-74bd980b44b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_1837daa9-77ee-4ed3-989f-74bd980b44b5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_b4d19523-7b04-4c38-8581-4a6723bf2261" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_b4d19523-7b04-4c38-8581-4a6723bf2261" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_09ab03e6-0d7d-4402-b4a5-479f2d1e8630" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_OtherAssets_09ab03e6-0d7d-4402-b4a5-479f2d1e8630" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_90a9cfcd-b5bf-449e-9b7c-f834ab242ed5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_Assets_90a9cfcd-b5bf-449e-9b7c-f834ab242ed5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_9849c986-f360-432c-9bd3-d225d4dc1144" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_SecuredDebt_9849c986-f360-432c-9bd3-d225d4dc1144" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_7b957dfe-02b7-4577-bb4b-be4c429ff37d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_OtherLiabilities_7b957dfe-02b7-4577-bb4b-be4c429ff37d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_694aeaf1-9113-47ce-a2f1-79c5b9819c96" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_Liabilities_694aeaf1-9113-47ce-a2f1-79c5b9819c96" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_8fe37f1f-6ba6-4319-b449-7a09d0521235" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_8fe37f1f-6ba6-4319-b449-7a09d0521235" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c781ee43-3be2-4d2e-9443-82902bd2a906" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_StockholdersEquity_c781ee43-3be2-4d2e-9443-82902bd2a906" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_72bc1b3b-d699-4ce3-b05c-1717a87f93a9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_MinorityInterest_72bc1b3b-d699-4ce3-b05c-1717a87f93a9" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_c109adfc-87db-438d-8ac7-8426ebef57f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_c109adfc-87db-438d-8ac7-8426ebef57f0" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_730509b2-c500-4907-aa0a-b5d0788028e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_4bb752da-b43d-4a29-a5a4-17953640451f" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_730509b2-c500-4907-aa0a-b5d0788028e8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_33f11feb-acc7-497f-927e-5c510c86a93a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_730509b2-c500-4907-aa0a-b5d0788028e8" xlink:to="loc_srt_ConsolidatedEntitiesAxis_33f11feb-acc7-497f-927e-5c510c86a93a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_33f11feb-acc7-497f-927e-5c510c86a93a_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_33f11feb-acc7-497f-927e-5c510c86a93a" xlink:to="loc_srt_ConsolidatedEntitiesDomain_33f11feb-acc7-497f-927e-5c510c86a93a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_b8872de8-4ae1-4ed2-852a-361543891fa9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_33f11feb-acc7-497f-927e-5c510c86a93a" xlink:to="loc_srt_ConsolidatedEntitiesDomain_b8872de8-4ae1-4ed2-852a-361543891fa9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_968c707d-7447-4157-a825-d22a0048a428" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_b8872de8-4ae1-4ed2-852a-361543891fa9" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_968c707d-7447-4157-a825-d22a0048a428" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails" xlink:type="simple" xlink:href="are-20230331.xsd#ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails" xlink:type="extended" id="ic47541e12f854c1fbd1167453a006524_ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_3e3739c0-c1d3-4dae-8983-a1f47eebd016" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_7c5b6cbf-f422-433c-82a1-a090ec6c3a72" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_3e3739c0-c1d3-4dae-8983-a1f47eebd016" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_7c5b6cbf-f422-433c-82a1-a090ec6c3a72" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_8de49682-08a5-49bd-b9ef-0ec5b5c200df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_3e3739c0-c1d3-4dae-8983-a1f47eebd016" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_8de49682-08a5-49bd-b9ef-0ec5b5c200df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:href="are-20230331.xsd#are_UnconsolidatedRealEstateJointVentureDebtAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_3e3739c0-c1d3-4dae-8983-a1f47eebd016" xlink:to="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_44cdf706-e322-4eea-912b-b850a8f2cde9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_44cdf706-e322-4eea-912b-b850a8f2cde9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_91896190-8500-43b5-943c-d95a65f49350" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_91896190-8500-43b5-943c-d95a65f49350" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_0189e680-eb55-4c94-be6f-9594d028eb7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_0189e680-eb55-4c94-be6f-9594d028eb7a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBorrowingCapacity_c223768f-c6e2-444c-8f14-21642b7935cd" xlink:href="are-20230331.xsd#are_DebtInstrumentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_are_DebtInstrumentBorrowingCapacity_c223768f-c6e2-444c-8f14-21642b7935cd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_74762e03-b1f0-415c-81e2-fc875d794992" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_us-gaap_LongTermDebt_74762e03-b1f0-415c-81e2-fc875d794992" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBasisSpreadOnVariableRateFloor_cad0d5bf-0f8c-4a95-beaa-fcbb76a3e0bd" xlink:href="are-20230331.xsd#are_DebtInstrumentBasisSpreadOnVariableRateFloor"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_4e48907a-7f59-43c2-9944-4ae0c8fd51af" xlink:to="loc_are_DebtInstrumentBasisSpreadOnVariableRateFloor_cad0d5bf-0f8c-4a95-beaa-fcbb76a3e0bd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_3e3739c0-c1d3-4dae-8983-a1f47eebd016" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_6f58236d-4814-49c6-b79d-b90dec0e8e54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:to="loc_us-gaap_DebtInstrumentAxis_6f58236d-4814-49c6-b79d-b90dec0e8e54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_6f58236d-4814-49c6-b79d-b90dec0e8e54_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_6f58236d-4814-49c6-b79d-b90dec0e8e54" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_6f58236d-4814-49c6-b79d-b90dec0e8e54_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_6f58236d-4814-49c6-b79d-b90dec0e8e54" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecuredDebtMaturingOn122324Member_6dbe082d-b1b5-4acc-a9e2-8be13efff4ee" xlink:href="are-20230331.xsd#are_SecuredDebtMaturingOn122324Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:to="loc_are_SecuredDebtMaturingOn122324Member_6dbe082d-b1b5-4acc-a9e2-8be13efff4ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Secureddebtmaturingon31025Member_eb4c4a19-f937-413e-a4e5-8daae57413d8" xlink:href="are-20230331.xsd#are_Secureddebtmaturingon31025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:to="loc_are_Secureddebtmaturingon31025Member_eb4c4a19-f937-413e-a4e5-8daae57413d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecuredDebtMaturingOn111026Member_bd76aba4-f0dd-4eff-b951-42e3c0549c29" xlink:href="are-20230331.xsd#are_SecuredDebtMaturingOn111026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:to="loc_are_SecuredDebtMaturingOn111026Member_bd76aba4-f0dd-4eff-b951-42e3c0549c29" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecuredDebtMaturingOn121026Member_2fcbef5d-cc6f-429f-8022-6d6ba8c4c182" xlink:href="are-20230331.xsd#are_SecuredDebtMaturingOn121026Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_bdf835ac-c211-496c-abb5-4bfec1d93ed2" xlink:to="loc_are_SecuredDebtMaturingOn121026Member_2fcbef5d-cc6f-429f-8022-6d6ba8c4c182" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_223d277b-9ff5-424c-a5c6-f1c4450c9887" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_223d277b-9ff5-424c-a5c6-f1c4450c9887" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_223d277b-9ff5-424c-a5c6-f1c4450c9887_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_223d277b-9ff5-424c-a5c6-f1c4450c9887" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_223d277b-9ff5-424c-a5c6-f1c4450c9887_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_223d277b-9ff5-424c-a5c6-f1c4450c9887" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1655and1715ThirdStreetMember_39ec6ba5-774a-4df4-a53c-e83788ad76fc" xlink:href="are-20230331.xsd#are_A1655and1715ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:to="loc_are_A1655and1715ThirdStreetMember_39ec6ba5-774a-4df4-a53c-e83788ad76fc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1450ResearchBoulevardMember_1a48b208-11bb-472d-bd16-1aac4e4f3c55" xlink:href="are-20230331.xsd#are_A1450ResearchBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:to="loc_are_A1450ResearchBoulevardMember_1a48b208-11bb-472d-bd16-1aac4e4f3c55" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A101WestDickmanStreetMember_8236db94-3843-4e44-b748-fb53ecb970bd" xlink:href="are-20230331.xsd#are_A101WestDickmanStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:to="loc_are_A101WestDickmanStreetMember_8236db94-3843-4e44-b748-fb53ecb970bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A14011413ResearchBoulevardMember_6a7da15c-bd6e-458d-93c0-74b7d492153a" xlink:href="are-20230331.xsd#are_A14011413ResearchBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:to="loc_are_A14011413ResearchBoulevardMember_6a7da15c-bd6e-458d-93c0-74b7d492153a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherunconsolidatedrealestatejointventuresMember_fe8e7d4a-1fb9-4176-b5fc-c53d379ab89a" xlink:href="are-20230331.xsd#are_OtherunconsolidatedrealestatejointventuresMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_4bbda88c-fb90-491b-8fba-e834a32add91" xlink:to="loc_are_OtherunconsolidatedrealestatejointventuresMember_fe8e7d4a-1fb9-4176-b5fc-c53d379ab89a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_255f2811-3b4e-4363-9a73-ab4f98f39e28" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:to="loc_us-gaap_VariableRateAxis_255f2811-3b4e-4363-9a73-ab4f98f39e28" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_255f2811-3b4e-4363-9a73-ab4f98f39e28_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_255f2811-3b4e-4363-9a73-ab4f98f39e28" xlink:to="loc_us-gaap_VariableRateDomain_255f2811-3b4e-4363-9a73-ab4f98f39e28_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_fcb5507b-7286-4eb3-9078-3bcda4983819" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_255f2811-3b4e-4363-9a73-ab4f98f39e28" xlink:to="loc_us-gaap_VariableRateDomain_fcb5507b-7286-4eb3-9078-3bcda4983819" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_9df15075-5d05-4cce-b83a-2f12f0a24eb5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_fcb5507b-7286-4eb3-9078-3bcda4983819" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_9df15075-5d05-4cce-b83a-2f12f0a24eb5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_4593006e-8b4f-459e-8324-34bfbbbee175" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_2a5690a2-5b93-4372-93d1-92788b6002dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_9b9c5929-bc33-4d12-b1dd-3c065e7ded3a" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_2a5690a2-5b93-4372-93d1-92788b6002dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_82e359da-3a3a-4a0e-91a6-bd151ccb593a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_2a5690a2-5b93-4372-93d1-92788b6002dc" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_82e359da-3a3a-4a0e-91a6-bd151ccb593a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/LeasesLessorDetails" xlink:type="simple" xlink:href="are-20230331.xsd#LeasesLessorDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/LeasesLessorDetails" xlink:type="extended" id="i6dc65dd0c15d4e5998f7280f13e76e22_LeasesLessorDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_84ad8c64-37b7-41eb-8bbb-3eb4e0a0e7e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_84ad8c64-37b7-41eb-8bbb-3eb4e0a0e7e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_13e6040a-d8ae-4886-a904-c4093b824086" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_13e6040a-d8ae-4886-a904-c4093b824086" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeaseDescriptionAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Landparcelsubjecttoleaseagreementthatcontainsapurchaseoption_d77903fc-775e-4fdd-a536-3390f1e6d195" xlink:href="are-20230331.xsd#are_Landparcelsubjecttoleaseagreementthatcontainsapurchaseoption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:to="loc_are_Landparcelsubjecttoleaseagreementthatcontainsapurchaseoption_d77903fc-775e-4fdd-a536-3390f1e6d195" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_97ff1b62-d781-45ee-a5a7-f9dc25d5c697" xlink:href="are-20230331.xsd#are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:to="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_97ff1b62-d781-45ee-a5a7-f9dc25d5c697" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RentCommenceDate_3fb5fd64-07ba-4180-8539-817a03cf06e6" xlink:href="are-20230331.xsd#are_RentCommenceDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:to="loc_are_RentCommenceDate_3fb5fd64-07ba-4180-8539-817a03cf06e6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseRemainingLeaseTerm_eee43d3e-6ef9-455e-aeba-e4134146e5cf" xlink:href="are-20230331.xsd#are_LessorOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:to="loc_are_LessorOperatingLeaseRemainingLeaseTerm_eee43d3e-6ef9-455e-aeba-e4134146e5cf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_e769bec9-1bb0-47cd-b774-395b69911e48" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_69dd5186-dabc-4005-aea7-92c47b07b0cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_69dd5186-dabc-4005-aea7-92c47b07b0cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_7db888be-1391-44ad-9730-6cd223cad033" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_7db888be-1391-44ad-9730-6cd223cad033" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bdb64462-c0be-41ea-976b-76ff4cb3e93d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_bdb64462-c0be-41ea-976b-76ff4cb3e93d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_492bfeb5-c057-47b9-82e6-10b9b6d56831" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_492bfeb5-c057-47b9-82e6-10b9b6d56831" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_e43cdd18-10a8-4958-b045-64b423332035" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_e43cdd18-10a8-4958-b045-64b423332035" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_4f375d95-d967-4a7f-8492-6e2ad02cf47d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_4f375d95-d967-4a7f-8492-6e2ad02cf47d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_e49fb77f-b48e-47a6-ac95-9d8267a3dccc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_b100be21-aa24-4ad2-99e8-8fd94ed77f7f" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_e49fb77f-b48e-47a6-ac95-9d8267a3dccc" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetInvestmentInLeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfDirectFinancingLeases_abe78d2e-747d-4cc5-b060-4ee299f1e2e0" xlink:href="are-20230331.xsd#are_NumberOfDirectFinancingLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_are_NumberOfDirectFinancingLeases_abe78d2e-747d-4cc5-b060-4ee299f1e2e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLease_a66507cc-991b-442d-bc1b-ad04fca2e15f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLease_a66507cc-991b-442d-bc1b-ad04fca2e15f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseRemainingLeaseTerm_7778775a-5e76-4bb5-8bd9-2b6a3a1ecc2c" xlink:href="are-20230331.xsd#are_LessorDirectFinancingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_are_LessorDirectFinancingLeaseRemainingLeaseTerm_7778775a-5e76-4bb5-8bd9-2b6a3a1ecc2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod_51c68323-7175-4bb1-a868-0e930714d779" xlink:href="are-20230331.xsd#are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod_51c68323-7175-4bb1-a868-0e930714d779" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_85db030f-e299-4c93-ac3d-cbbdce6711c3" xlink:href="are-20230331.xsd#are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_85db030f-e299-4c93-ac3d-cbbdce6711c3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss_b75bf987-3fc1-440c-89fd-43ade8595e74" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss_b75bf987-3fc1-440c-89fd-43ade8595e74" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_c04dfb21-4248-41a4-93aa-d19367ec1ed1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_c04dfb21-4248-41a4-93aa-d19367ec1ed1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DirectFinancingLeaseUnearnedIncome_6b9f9215-fb8f-4200-b237-d275b9a9c84d" xlink:href="are-20230331.xsd#are_DirectFinancingLeaseUnearnedIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:to="loc_are_DirectFinancingLeaseUnearnedIncome_6b9f9215-fb8f-4200-b237-d275b9a9c84d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss_5f43879d-5a49-48af-8e47-ef594b30a96b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:to="loc_us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss_5f43879d-5a49-48af-8e47-ef594b30a96b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLease_f01dca53-14aa-4b19-b88f-e1da9e0534aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetInvestmentInLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_99d70d53-56bb-4971-8d29-de961881ac5f" xlink:to="loc_us-gaap_NetInvestmentInLease_f01dca53-14aa-4b19-b88f-e1da9e0534aa" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_22475d60-7898-4a1b-97eb-13cac504db70" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear_8f7ce8ba-d124-4974-a0c5-eda09fbb3e58" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear_8f7ce8ba-d124-4974-a0c5-eda09fbb3e58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths_80d8126b-fdb0-47f7-8331-6816cea56d1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths_80d8126b-fdb0-47f7-8331-6816cea56d1d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears_2cbecc63-247f-4376-bdab-f896a32bee1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears_2cbecc63-247f-4376-bdab-f896a32bee1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears_aea2bc4f-8dc9-4fac-8acc-dc1e347cf6dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears_aea2bc4f-8dc9-4fac-8acc-dc1e347cf6dc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears_9065a92a-3258-4287-af02-b1a197ec4a29" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears_9065a92a-3258-4287-af02-b1a197ec4a29" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter_5d97f3f2-56f7-48b4-999a-84441f55a07c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_2ea2b52a-e390-4d39-850d-08fb31e6b730" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter_5d97f3f2-56f7-48b4-999a-84441f55a07c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_71fe9b0e-1df8-4fa0-955c-2fb0b0a2182a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:href="are-20230331.xsd#are_IncomefromrentalsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_398f3714-3330-4d65-8c60-bf7c826d44b7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_398f3714-3330-4d65-8c60-bf7c826d44b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_a99567fd-724a-459f-af95-5b8858fd936a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_a99567fd-724a-459f-af95-5b8858fd936a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseIncome_f5e3bde6-9c91-44a4-8a6c-b616b94c1a55" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:to="loc_us-gaap_LeaseIncome_f5e3bde6-9c91-44a4-8a6c-b616b94c1a55" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_b4d5845b-894a-4ebe-8457-abd3afb3e9ab" xlink:href="are-20230331.xsd#are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:to="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_b4d5845b-894a-4ebe-8457-abd3afb3e9ab" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_f1612b53-f588-4b1a-a07f-c34e32ff98ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_1ee6b4c5-1fbf-4645-8344-f8ce3deca9b8" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_f1612b53-f588-4b1a-a07f-c34e32ff98ee" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_3bac8120-d86a-4d52-9b8b-95d5596dc526" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:to="loc_srt_ProductOrServiceAxis_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504" xlink:to="loc_srt_ProductsAndServicesDomain_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_5e449036-b8dc-4d4f-a058-d3aa92e1cd9b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_9c2b8c5d-6aaa-48a6-b1a0-d9e5f74d8504" xlink:to="loc_srt_ProductsAndServicesDomain_5e449036-b8dc-4d4f-a058-d3aa92e1cd9b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_a923c0a5-60b7-4040-b68a-dfdd29d84f60" xlink:href="are-20230331.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_5e449036-b8dc-4d4f-a058-d3aa92e1cd9b" xlink:to="loc_are_IncomefromrentalsMember_a923c0a5-60b7-4040-b68a-dfdd29d84f60" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_e8ff67c0-df12-4ad7-a5d9-1216d40305ba" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:to="loc_srt_StatementGeographicalAxis_e8ff67c0-df12-4ad7-a5d9-1216d40305ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_e8ff67c0-df12-4ad7-a5d9-1216d40305ba_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_e8ff67c0-df12-4ad7-a5d9-1216d40305ba" xlink:to="loc_srt_SegmentGeographicalDomain_e8ff67c0-df12-4ad7-a5d9-1216d40305ba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_7101fd2c-8159-4104-8f34-29ee363aadfe" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_e8ff67c0-df12-4ad7-a5d9-1216d40305ba" xlink:to="loc_srt_SegmentGeographicalDomain_7101fd2c-8159-4104-8f34-29ee363aadfe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_d8e39528-78c8-4bf7-96c5-c41694452069" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_7101fd2c-8159-4104-8f34-29ee363aadfe" xlink:to="loc_srt_NorthAmericaMember_d8e39528-78c8-4bf7-96c5-c41694452069" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_785f2e5e-85de-4bc3-be55-1b675cdc3a96" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_785f2e5e-85de-4bc3-be55-1b675cdc3a96" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_785f2e5e-85de-4bc3-be55-1b675cdc3a96_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_785f2e5e-85de-4bc3-be55-1b675cdc3a96" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_785f2e5e-85de-4bc3-be55-1b675cdc3a96_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_b9a00b00-2532-4c14-9d07-578053a78a6a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_785f2e5e-85de-4bc3-be55-1b675cdc3a96" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_b9a00b00-2532-4c14-9d07-578053a78a6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember_41fb0a63-31b7-4620-93a1-a2b3e30e42c8" xlink:href="are-20230331.xsd#are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_b9a00b00-2532-4c14-9d07-578053a78a6a" xlink:to="loc_are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember_41fb0a63-31b7-4620-93a1-a2b3e30e42c8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c8c3a521-09f6-4fbf-a15a-b702d8ef0113" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c8c3a521-09f6-4fbf-a15a-b702d8ef0113" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c8c3a521-09f6-4fbf-a15a-b702d8ef0113_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c8c3a521-09f6-4fbf-a15a-b702d8ef0113" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_c8c3a521-09f6-4fbf-a15a-b702d8ef0113_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_cbd9305a-c3aa-489f-a24a-a7785119e982" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_c8c3a521-09f6-4fbf-a15a-b702d8ef0113" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_cbd9305a-c3aa-489f-a24a-a7785119e982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_1c3fe972-6659-42b0-9bce-59ba1af33a6c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_cbd9305a-c3aa-489f-a24a-a7785119e982" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_1c3fe972-6659-42b0-9bce-59ba1af33a6c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermAxis_06a9a841-f2f3-4511-a477-669360d99dca" xlink:href="are-20230331.xsd#are_PurchaseOptionTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_f50b3e79-ba58-4130-afa8-f534fd70f4d2" xlink:to="loc_are_PurchaseOptionTermAxis_06a9a841-f2f3-4511-a477-669360d99dca" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermDomain_06a9a841-f2f3-4511-a477-669360d99dca_default" xlink:href="are-20230331.xsd#are_PurchaseOptionTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PurchaseOptionTermAxis_06a9a841-f2f3-4511-a477-669360d99dca" xlink:to="loc_are_PurchaseOptionTermDomain_06a9a841-f2f3-4511-a477-669360d99dca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermDomain_396bdf0f-b92d-41e8-8492-a02a1bacb188" xlink:href="are-20230331.xsd#are_PurchaseOptionTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PurchaseOptionTermAxis_06a9a841-f2f3-4511-a477-669360d99dca" xlink:to="loc_are_PurchaseOptionTermDomain_396bdf0f-b92d-41e8-8492-a02a1bacb188" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermOneMember_fa26bcc1-526d-4725-a8ee-c16227162d32" xlink:href="are-20230331.xsd#are_PurchaseOptionTermOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_396bdf0f-b92d-41e8-8492-a02a1bacb188" xlink:to="loc_are_PurchaseOptionTermOneMember_fa26bcc1-526d-4725-a8ee-c16227162d32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermTwoMember_71e77c21-bdcc-409c-8807-26c542f7d588" xlink:href="are-20230331.xsd#are_PurchaseOptionTermTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_396bdf0f-b92d-41e8-8492-a02a1bacb188" xlink:to="loc_are_PurchaseOptionTermTwoMember_71e77c21-bdcc-409c-8807-26c542f7d588" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermThreeMember_005e379f-02a8-4238-8c54-a10ae5ffbf8b" xlink:href="are-20230331.xsd#are_PurchaseOptionTermThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_396bdf0f-b92d-41e8-8492-a02a1bacb188" xlink:to="loc_are_PurchaseOptionTermThreeMember_005e379f-02a8-4238-8c54-a10ae5ffbf8b" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/LeasesLesseeDetails" xlink:type="simple" xlink:href="are-20230331.xsd#LeasesLesseeDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/LeasesLesseeDetails" xlink:type="extended" id="if0a351e177fb44079e5bdb16ba4d232e_LeasesLesseeDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundAndOperatingLeaseObligationDue_373f77e4-9dc0-42b1-b33e-760706a0b769" xlink:href="are-20230331.xsd#are_GroundAndOperatingLeaseObligationDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_GroundAndOperatingLeaseObligationDue_373f77e4-9dc0-42b1-b33e-760706a0b769" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_c61ede69-4366-40a5-aa29-9907303ec6e1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeaseLiability_c61ede69-4366-40a5-aa29-9907303ec6e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_7a2f00c5-e1a7-438f-8641-4a2e090018d3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_7a2f00c5-e1a7-438f-8641-4a2e090018d3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_cae57066-839b-4e7f-88fe-76dd998e4143" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_cae57066-839b-4e7f-88fe-76dd998e4143" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_561278b0-3119-45d9-9e09-94ba5aa22906" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_561278b0-3119-45d9-9e09-94ba5aa22906" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfPropertiesSubjectToGroundLeases_ae64bbe3-09fe-4077-9ff8-f0e68e0258cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfPropertiesSubjectToGroundLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_NumberOfPropertiesSubjectToGroundLeases_ae64bbe3-09fe-4077-9ff8-f0e68e0258cf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PercentageOfPropertiesSubjectToGroundLeases_82473c65-f463-49f3-8a79-03cbd2ee65e1" xlink:href="are-20230331.xsd#are_PercentageOfPropertiesSubjectToGroundLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_PercentageOfPropertiesSubjectToGroundLeases_82473c65-f463-49f3-8a79-03cbd2ee65e1" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundLeaseRelatedToOperatingPropertyNetBookValue_592b76ec-35f7-42fd-a046-1a3497f9addb" xlink:href="are-20230331.xsd#are_GroundLeaseRelatedToOperatingPropertyNetBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_GroundLeaseRelatedToOperatingPropertyNetBookValue_592b76ec-35f7-42fd-a046-1a3497f9addb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundLeaseObligationRemainingLeaseTerm_bf7f9849-dd9f-417d-92bc-42ae359bf1f9" xlink:href="are-20230331.xsd#are_GroundLeaseObligationRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_GroundLeaseObligationRemainingLeaseTerm_bf7f9849-dd9f-417d-92bc-42ae359bf1f9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingLeaseObligationRemainingLeaseTerm_e6350176-3b1a-4040-933d-dfabc2d536e4" xlink:href="are-20230331.xsd#are_OperatingLeaseObligationRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_OperatingLeaseObligationRemainingLeaseTerm_e6350176-3b1a-4040-933d-dfabc2d536e4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_fa2c6c2e-08c3-4871-a24d-3483a272b1e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeasePayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeasePayments_fa2c6c2e-08c3-4871-a24d-3483a272b1e8" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfPropertiesAssociatedWithLeaseExtensionsExecuted_41300f37-9fec-4f16-9570-55fac5b33cfc" xlink:href="are-20230331.xsd#are_NumberOfPropertiesAssociatedWithLeaseExtensionsExecuted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_are_NumberOfPropertiesAssociatedWithLeaseExtensionsExecuted_41300f37-9fec-4f16-9570-55fac5b33cfc" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_946526da-d950-47cd-a0ff-152daf0028b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_946526da-d950-47cd-a0ff-152daf0028b0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_f577bc37-3570-4d18-aeb6-74ee94efa59f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_f577bc37-3570-4d18-aeb6-74ee94efa59f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_b4963131-c08f-4b0a-a55e-e67a1515f537" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_b4963131-c08f-4b0a-a55e-e67a1515f537" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_47d3a4d2-aa41-49ed-8d6a-825455ea3311" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_47d3a4d2-aa41-49ed-8d6a-825455ea3311" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_9b7ba9b9-3706-4531-af7f-b872ccaef2d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_9b7ba9b9-3706-4531-af7f-b872ccaef2d0" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_d33015a3-87c0-4ff1-94d3-c484da3db9cb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_d33015a3-87c0-4ff1-94d3-c484da3db9cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_85cd4223-c235-413c-afd9-a8e8f24fe070" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_85cd4223-c235-413c-afd9-a8e8f24fe070" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_c3453fff-13fd-47f3-8de6-7ad66d02dd46" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_d09994e9-3b28-4e5a-a9b0-5900b7cc8136" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_c3453fff-13fd-47f3-8de6-7ad66d02dd46" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_3e7fe60f-6243-4638-8968-e050c0d3d8c2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostAbstract_e654519e-8e4f-42c3-8289-fec7edcacf2b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_LeaseCostAbstract_e654519e-8e4f-42c3-8289-fec7edcacf2b" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_1f185d33-4ac9-4f73-bef5-bc38943531f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_e654519e-8e4f-42c3-8289-fec7edcacf2b" xlink:to="loc_us-gaap_OperatingLeaseCost_1f185d33-4ac9-4f73-bef5-bc38943531f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CapitalizedLeaseCosts_d036c44c-469f-4a77-ac45-ae84b9d95956" xlink:href="are-20230331.xsd#are_CapitalizedLeaseCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_e654519e-8e4f-42c3-8289-fec7edcacf2b" xlink:to="loc_are_CapitalizedLeaseCosts_d036c44c-469f-4a77-ac45-ae84b9d95956" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost_795fca0d-62c2-462e-a44c-6d40d2b8e4ac" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_e654519e-8e4f-42c3-8289-fec7edcacf2b" xlink:to="loc_us-gaap_LeaseCost_795fca0d-62c2-462e-a44c-6d40d2b8e4ac" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_d137431c-07b9-45d8-adfb-266635523ed4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_98bab767-7879-439c-9401-532d02fc5df1" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_d137431c-07b9-45d8-adfb-266635523ed4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_84304927-df0d-4b2c-bfc8-9b82dd706697" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_d137431c-07b9-45d8-adfb-266635523ed4" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_84304927-df0d-4b2c-bfc8-9b82dd706697" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_84304927-df0d-4b2c-bfc8-9b82dd706697_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_84304927-df0d-4b2c-bfc8-9b82dd706697" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_84304927-df0d-4b2c-bfc8-9b82dd706697_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e906a0a-a03c-499e-8270-a6b337bdaf26" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_84304927-df0d-4b2c-bfc8-9b82dd706697" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e906a0a-a03c-499e-8270-a6b337bdaf26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundandOperatingLeasesMember_0e0aa3e9-56d0-46d7-ad40-50740c2508ec" xlink:href="are-20230331.xsd#are_GroundandOperatingLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e906a0a-a03c-499e-8270-a6b337bdaf26" xlink:to="loc_are_GroundandOperatingLeasesMember_0e0aa3e9-56d0-46d7-ad40-50740c2508ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertyWithGroundLeaseMember_18762d04-2b07-4c95-be46-5799d98b987d" xlink:href="are-20230331.xsd#are_OperatingPropertyWithGroundLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e906a0a-a03c-499e-8270-a6b337bdaf26" xlink:to="loc_are_OperatingPropertyWithGroundLeaseMember_18762d04-2b07-4c95-be46-5799d98b987d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_1747d2c0-194c-40fe-ad33-28f3c63cabd1" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_d137431c-07b9-45d8-adfb-266635523ed4" xlink:to="loc_srt_RangeAxis_1747d2c0-194c-40fe-ad33-28f3c63cabd1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_1747d2c0-194c-40fe-ad33-28f3c63cabd1_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_1747d2c0-194c-40fe-ad33-28f3c63cabd1" xlink:to="loc_srt_RangeMember_1747d2c0-194c-40fe-ad33-28f3c63cabd1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dba6d563-3514-414e-a724-4f93f724433a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_1747d2c0-194c-40fe-ad33-28f3c63cabd1" xlink:to="loc_srt_RangeMember_dba6d563-3514-414e-a724-4f93f724433a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_21e7e16c-a486-45a0-ae9c-2a0fbf31b1b9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dba6d563-3514-414e-a724-4f93f724433a" xlink:to="loc_srt_MinimumMember_21e7e16c-a486-45a0-ae9c-2a0fbf31b1b9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_bf8eb570-6e62-4d97-9d05-f25a0e4d158b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dba6d563-3514-414e-a724-4f93f724433a" xlink:to="loc_srt_MaximumMember_bf8eb570-6e62-4d97-9d05-f25a0e4d158b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_bf79f749-53da-4a88-8bf3-a41b623b9b08" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_d137431c-07b9-45d8-adfb-266635523ed4" xlink:to="loc_srt_StatementGeographicalAxis_bf79f749-53da-4a88-8bf3-a41b623b9b08" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_bf79f749-53da-4a88-8bf3-a41b623b9b08_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_bf79f749-53da-4a88-8bf3-a41b623b9b08" xlink:to="loc_srt_SegmentGeographicalDomain_bf79f749-53da-4a88-8bf3-a41b623b9b08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_ad63bd08-e4e6-4a6a-87b8-e5171ecabbdf" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_bf79f749-53da-4a88-8bf3-a41b623b9b08" xlink:to="loc_srt_SegmentGeographicalDomain_ad63bd08-e4e6-4a6a-87b8-e5171ecabbdf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SanFranciscoBayAreaMember_5c0a585e-cbfb-4b2b-9760-0ca49d537a93" xlink:href="are-20230331.xsd#are_SanFranciscoBayAreaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_ad63bd08-e4e6-4a6a-87b8-e5171ecabbdf" xlink:to="loc_are_SanFranciscoBayAreaMember_5c0a585e-cbfb-4b2b-9760-0ca49d537a93" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/CashcashequivalentsandrestrictedcashDetails" xlink:type="simple" xlink:href="are-20230331.xsd#CashcashequivalentsandrestrictedcashDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/CashcashequivalentsandrestrictedcashDetails" xlink:type="extended" id="if0917c7d01174961ad9a72acb48811ec_CashcashequivalentsandrestrictedcashDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_83a1226a-96d2-461f-93fe-a85ce4fc09d6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_c2ceac25-518b-4ae8-8b68-335aff8f4f5d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_83a1226a-96d2-461f-93fe-a85ce4fc09d6" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_c2ceac25-518b-4ae8-8b68-335aff8f4f5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_392f1e4f-77e5-46f4-b944-f73876f4ead2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_83a1226a-96d2-461f-93fe-a85ce4fc09d6" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_392f1e4f-77e5-46f4-b944-f73876f4ead2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_123ca68d-e918-4608-9232-2c1603a9b3ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_83a1226a-96d2-461f-93fe-a85ce4fc09d6" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_123ca68d-e918-4608-9232-2c1603a9b3ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_eb6cb74a-b1df-4f9c-b471-2933b26f320e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_83a1226a-96d2-461f-93fe-a85ce4fc09d6" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_eb6cb74a-b1df-4f9c-b471-2933b26f320e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_aef98ad8-11ae-499c-859a-722366a1dd16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_eb6cb74a-b1df-4f9c-b471-2933b26f320e" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_aef98ad8-11ae-499c-859a-722366a1dd16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_aef98ad8-11ae-499c-859a-722366a1dd16_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_aef98ad8-11ae-499c-859a-722366a1dd16" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_aef98ad8-11ae-499c-859a-722366a1dd16_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6b974c07-3283-47ed-949d-fbec962138ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_aef98ad8-11ae-499c-859a-722366a1dd16" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6b974c07-3283-47ed-949d-fbec962138ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FundsheldinescrowrelatedtoconstructionprojectsandinvestingactivitiesMember_066ca8a1-a002-4c75-99ce-34fd9e78f0c1" xlink:href="are-20230331.xsd#are_FundsheldinescrowrelatedtoconstructionprojectsandinvestingactivitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6b974c07-3283-47ed-949d-fbec962138ed" xlink:to="loc_are_FundsheldinescrowrelatedtoconstructionprojectsandinvestingactivitiesMember_066ca8a1-a002-4c75-99ce-34fd9e78f0c1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherrestrictedcashMember_ff3fa7a2-6f86-4aaf-b20d-ed43d429ac6d" xlink:href="are-20230331.xsd#are_OtherrestrictedcashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_6b974c07-3283-47ed-949d-fbec962138ed" xlink:to="loc_are_OtherrestrictedcashMember_ff3fa7a2-6f86-4aaf-b20d-ed43d429ac6d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsSummaryofInvestmentsDetails" xlink:type="simple" xlink:href="are-20230331.xsd#InvestmentsSummaryofInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsSummaryofInvestmentsDetails" xlink:type="extended" id="i53e0483089a3441da45bb8a7746b8f8b_InvestmentsSummaryofInvestmentsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CostMethodInvestmentOwnershipPercentage_b3b7e23f-f051-496b-82d5-43d904191431" xlink:href="are-20230331.xsd#are_CostMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_CostMethodInvestmentOwnershipPercentage_b3b7e23f-f051-496b-82d5-43d904191431" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfEquityMethodInvestments_1c1e9efb-389f-42f5-a397-143d8921be7f" xlink:href="are-20230331.xsd#are_NumberOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_NumberOfEquityMethodInvestments_1c1e9efb-389f-42f5-a397-143d8921be7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments_dc3473e6-f00b-41ff-8872-81bf8caa5a97" xlink:href="are-20230331.xsd#are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments_dc3473e6-f00b-41ff-8872-81bf8caa5a97" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedPartnershipMaximumExpirationTerms_337c4372-b2d4-4404-bec5-381b8658c24b" xlink:href="are-20230331.xsd#are_LimitedPartnershipMaximumExpirationTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_LimitedPartnershipMaximumExpirationTerms_337c4372-b2d4-4404-bec5-381b8658c24b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1_fadaa591-050c-4140-9433-57fbdc785feb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1_fadaa591-050c-4140-9433-57fbdc785feb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedPartnershipLiquidationExpectedInitialTermInYears_e2b7987e-d524-4b82-a23f-5a932100dc29" xlink:href="are-20230331.xsd#are_LimitedPartnershipLiquidationExpectedInitialTermInYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_LimitedPartnershipLiquidationExpectedInitialTermInYears_e2b7987e-d524-4b82-a23f-5a932100dc29" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount_7e424944-9b70-4818-af57-f4b28303b47f" xlink:href="are-20230331.xsd#are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount_7e424944-9b70-4818-af57-f4b28303b47f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount_a6396eda-6862-4f0d-8fef-277dbd562e66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount_a6396eda-6862-4f0d-8fef-277dbd562e66" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount_fd56a026-e3af-4ff5-9c2d-502dcef10103" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount_fd56a026-e3af-4ff5-9c2d-502dcef10103" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_62ce7790-297c-47d0-8469-b124146d0eee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_62ce7790-297c-47d0-8469-b124146d0eee" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AnnualadjustmentsrecognizedoninvestmentsinprivatelyheldentitiesthatdonotreportNAV_5a81de97-c5fb-4143-978b-61a3b85078a7" xlink:href="are-20230331.xsd#are_AnnualadjustmentsrecognizedoninvestmentsinprivatelyheldentitiesthatdonotreportNAV"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_AnnualadjustmentsrecognizedoninvestmentsinprivatelyheldentitiesthatdonotreportNAV_5a81de97-c5fb-4143-978b-61a3b85078a7" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount_4812f971-9d43-40c0-9eb6-b8dd5fbd2531" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount_4812f971-9d43-40c0-9eb6-b8dd5fbd2531" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount_3980f6a7-b374-41a7-97b1-4696007d1c0e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount_3980f6a7-b374-41a7-97b1-4696007d1c0e" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_aa27d871-b8c0-4b48-87d6-f9a08c523db6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_aa27d871-b8c0-4b48-87d6-f9a08c523db6" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:href="are-20230331.xsd#are_SummaryofInvestmentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCost_748736d8-1f85-4e6a-9da4-e44afe4c9e15" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCost_748736d8-1f85-4e6a-9da4-e44afe4c9e15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CumulativeUnrealizedGainsOnInvestments_8b869ebc-f086-4a90-9bf1-10799fcbd8f8" xlink:href="are-20230331.xsd#are_CumulativeUnrealizedGainsOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_are_CumulativeUnrealizedGainsOnInvestments_8b869ebc-f086-4a90-9bf1-10799fcbd8f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CumulativeUnrealizedLossesOnInvestments_fff71987-5a1c-4ed8-a5bd-1097bace57ef" xlink:href="are-20230331.xsd#are_CumulativeUnrealizedLossesOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_are_CumulativeUnrealizedLossesOnInvestments_fff71987-5a1c-4ed8-a5bd-1097bace57ef" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_ab6da72d-7492-4ffd-bb85-7cbbdb32317d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_ab6da72d-7492-4ffd-bb85-7cbbdb32317d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_909e45ba-fc64-4eff-991c-482e6050804f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_909e45ba-fc64-4eff-991c-482e6050804f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_84969817-f11d-4971-b711-bed43332331b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_us-gaap_EquityMethodInvestments_84969817-f11d-4971-b711-bed43332331b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_09ccb8e5-4017-49cf-b602-5b8871e0a2c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_SummaryofInvestmentAbstract_3a45ce3e-803c-42f9-aad0-102c96d18e0e" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_09ccb8e5-4017-49cf-b602-5b8871e0a2c4" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeNetAbstract_bf180c2d-6b2f-47a3-a58d-1557d73f2176" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentIncomeNetAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_InvestmentIncomeNetAbstract_bf180c2d-6b2f-47a3-a58d-1557d73f2176" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_02cbd960-17ff-4a86-bbad-711a4e617b36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiRealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentIncomeNetAbstract_bf180c2d-6b2f-47a3-a58d-1557d73f2176" xlink:to="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_02cbd960-17ff-4a86-bbad-711a4e617b36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_7dabd63a-6a4e-415f-bdd2-46c78129e1e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentIncomeNetAbstract_bf180c2d-6b2f-47a3-a58d-1557d73f2176" xlink:to="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_7dabd63a-6a4e-415f-bdd2-46c78129e1e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_e6cbbcc9-e906-4acb-92d4-35a28ba09b9d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentIncomeNetAbstract_bf180c2d-6b2f-47a3-a58d-1557d73f2176" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_e6cbbcc9-e906-4acb-92d4-35a28ba09b9d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentsTable_8c6fc48f-f19a-4506-9383-ca9fc0f86730" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentsLineItems_6deea5d8-4423-4b97-a9b2-55c9667b4170" xlink:to="loc_us-gaap_ScheduleOfInvestmentsTable_8c6fc48f-f19a-4506-9383-ca9fc0f86730" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_cd5fc625-567b-4721-9676-8f6cba7e9512" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_8c6fc48f-f19a-4506-9383-ca9fc0f86730" xlink:to="loc_us-gaap_InvestmentTypeAxis_cd5fc625-567b-4721-9676-8f6cba7e9512" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_cd5fc625-567b-4721-9676-8f6cba7e9512_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_cd5fc625-567b-4721-9676-8f6cba7e9512" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_cd5fc625-567b-4721-9676-8f6cba7e9512_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_cd5fc625-567b-4721-9676-8f6cba7e9512" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinpubliclytradedcompaniesMember_6423b63e-b2d3-485f-b20f-ff000993e953" xlink:href="are-20230331.xsd#are_InvestmentsinpubliclytradedcompaniesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:to="loc_are_InvestmentsinpubliclytradedcompaniesMember_6423b63e-b2d3-485f-b20f-ff000993e953" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedpartnershipsMember_d6d389d9-50c3-4142-aab3-bfc70df901d5" xlink:href="are-20230331.xsd#are_LimitedpartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:to="loc_are_LimitedpartnershipsMember_d6d389d9-50c3-4142-aab3-bfc70df901d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_7ffac14c-5ee0-412a-8dbd-301390776862" xlink:href="are-20230331.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_7ffac14c-5ee0-412a-8dbd-301390776862" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TotalInvestmentsHeldMember_198f505e-703b-48c2-b3f0-f9b90476c2cd" xlink:href="are-20230331.xsd#are_TotalInvestmentsHeldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_e87e1f1c-3583-4b8e-96e4-c06f2d781f6a" xlink:to="loc_are_TotalInvestmentsHeldMember_198f505e-703b-48c2-b3f0-f9b90476c2cd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_245ac3dc-26b6-4b27-8dae-d073b0fc50eb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_8c6fc48f-f19a-4506-9383-ca9fc0f86730" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_245ac3dc-26b6-4b27-8dae-d073b0fc50eb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_245ac3dc-26b6-4b27-8dae-d073b0fc50eb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_245ac3dc-26b6-4b27-8dae-d073b0fc50eb" xlink:to="loc_us-gaap_TypeOfAdoptionMember_245ac3dc-26b6-4b27-8dae-d073b0fc50eb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_d6e861f0-f887-491d-ba95-2ac8f8d1efab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_245ac3dc-26b6-4b27-8dae-d073b0fc50eb" xlink:to="loc_us-gaap_TypeOfAdoptionMember_d6e861f0-f887-491d-ba95-2ac8f8d1efab" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithobservablepricechangeMember_c97f51cd-138a-40c4-97b1-2037cc782157" xlink:href="are-20230331.xsd#are_EntitieswithobservablepricechangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_d6e861f0-f887-491d-ba95-2ac8f8d1efab" xlink:to="loc_are_EntitieswithobservablepricechangeMember_c97f51cd-138a-40c4-97b1-2037cc782157" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithoutobservablepricechangesMember_5ab88622-e172-49d3-8be1-9e4bee7a058a" xlink:href="are-20230331.xsd#are_EntitieswithoutobservablepricechangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_d6e861f0-f887-491d-ba95-2ac8f8d1efab" xlink:to="loc_are_EntitieswithoutobservablepricechangesMember_5ab88622-e172-49d3-8be1-9e4bee7a058a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_2a62c602-c6f8-433d-991a-4f235ca9f6a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentsTable_8c6fc48f-f19a-4506-9383-ca9fc0f86730" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_2a62c602-c6f8-433d-991a-4f235ca9f6a7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2a62c602-c6f8-433d-991a-4f235ca9f6a7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_2a62c602-c6f8-433d-991a-4f235ca9f6a7" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_2a62c602-c6f8-433d-991a-4f235ca9f6a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0f2c9a4e-f008-4c66-a275-49628c5ecb01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_2a62c602-c6f8-433d-991a-4f235ca9f6a7" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0f2c9a4e-f008-4c66-a275-49628c5ecb01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_c849e018-7df5-4845-b16b-77cc2f429fd1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityMethodInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_0f2c9a4e-f008-4c66-a275-49628c5ecb01" xlink:to="loc_us-gaap_EquityMethodInvestmentsMember_c849e018-7df5-4845-b16b-77cc2f429fd1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails" xlink:type="simple" xlink:href="are-20230331.xsd#FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails" xlink:type="extended" id="i42acfecd4e004c40b5610123842475ef_FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TransfersInFairValueHierarchy_7dd7e867-337f-43c7-ae02-9c6d9a70ac76" xlink:href="are-20230331.xsd#are_TransfersInFairValueHierarchy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:to="loc_are_TransfersInFairValueHierarchy_7dd7e867-337f-43c7-ae02-9c6d9a70ac76" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_43cbf265-fab2-4b55-afeb-f43cdf458bd6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_43cbf265-fab2-4b55-afeb-f43cdf458bd6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue_7cb38d92-fb35-4707-a22f-324526b23cee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:to="loc_us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue_7cb38d92-fb35-4707-a22f-324526b23cee" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_9d8bba94-a9c0-4bd6-bfcb-cd6f5acc9c9c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_9d8bba94-a9c0-4bd6-bfcb-cd6f5acc9c9c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_3d10ddad-ac68-4368-ad52-bbb4caf14607" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_SecuredDebt_3d10ddad-ac68-4368-ad52-bbb4caf14607" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_001fca74-b81c-4c6a-b02e-f7a24c973e19" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NotesPayableFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_001fca74-b81c-4c6a-b02e-f7a24c973e19" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorLongTermNotes_55cdd22d-6da2-45cc-bcfc-7afb3157546c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorLongTermNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_SeniorLongTermNotes_55cdd22d-6da2-45cc-bcfc-7afb3157546c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SeniorNotesFairValueDisclosure_33988adf-2bbc-497b-bb67-da23ddd51703" xlink:href="are-20230331.xsd#are_SeniorNotesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_are_SeniorNotesFairValueDisclosure_33988adf-2bbc-497b-bb67-da23ddd51703" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_917c7741-8703-492b-862f-6b7414b276aa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_LineOfCredit_917c7741-8703-492b-862f-6b7414b276aa" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditFairValueDisclosure_74456ccd-ba0c-48e3-b6da-b1b30979fd50" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LinesOfCreditFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_LinesOfCreditFairValueDisclosure_74456ccd-ba0c-48e3-b6da-b1b30979fd50" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_4251ab7e-02c2-4bc4-b1c6-9e541936a67a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_us-gaap_CommercialPaper_4251ab7e-02c2-4bc4-b1c6-9e541936a67a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommercialPaperFairValueDisclosure_391ab732-c25f-4640-93a5-8b6cfdae64d4" xlink:href="are-20230331.xsd#are_CommercialPaperFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_73660472-459e-40c4-9b2d-b351eb358d24" xlink:to="loc_are_CommercialPaperFairValueDisclosure_391ab732-c25f-4640-93a5-8b6cfdae64d4" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_2e311f0f-190d-4876-94dc-a2b31fdea81e" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_380c6b3e-e6ad-4449-9e35-be8ba5302f12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_380c6b3e-e6ad-4449-9e35-be8ba5302f12" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_380c6b3e-e6ad-4449-9e35-be8ba5302f12_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_380c6b3e-e6ad-4449-9e35-be8ba5302f12" xlink:to="loc_us-gaap_TypeOfAdoptionMember_380c6b3e-e6ad-4449-9e35-be8ba5302f12_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_2d6bdc42-948b-4c9d-9529-26c033ae42f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_380c6b3e-e6ad-4449-9e35-be8ba5302f12" xlink:to="loc_us-gaap_TypeOfAdoptionMember_2d6bdc42-948b-4c9d-9529-26c033ae42f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithoutobservablepricechangesMember_13ae9783-9a97-47d3-a12d-8c67dc209f6a" xlink:href="are-20230331.xsd#are_EntitieswithoutobservablepricechangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_2d6bdc42-948b-4c9d-9529-26c033ae42f0" xlink:to="loc_are_EntitieswithoutobservablepricechangesMember_13ae9783-9a97-47d3-a12d-8c67dc209f6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_63f2236b-9ca5-4e45-b151-467ae33b6710" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_InvestmentTypeAxis_63f2236b-9ca5-4e45-b151-467ae33b6710" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_63f2236b-9ca5-4e45-b151-467ae33b6710_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_63f2236b-9ca5-4e45-b151-467ae33b6710" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_63f2236b-9ca5-4e45-b151-467ae33b6710_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_5f543b4e-dca4-471c-a3fd-aad3ded11e68" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_63f2236b-9ca5-4e45-b151-467ae33b6710" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_5f543b4e-dca4-471c-a3fd-aad3ded11e68" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinpubliclytradedcompaniesMember_d4341d31-9713-4949-9b12-3e24d0feb13f" xlink:href="are-20230331.xsd#are_InvestmentsinpubliclytradedcompaniesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_5f543b4e-dca4-471c-a3fd-aad3ded11e68" xlink:to="loc_are_InvestmentsinpubliclytradedcompaniesMember_d4341d31-9713-4949-9b12-3e24d0feb13f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedpartnershipsMember_5d5b5d1c-a1db-4a17-ae25-853f77a98f40" xlink:href="are-20230331.xsd#are_LimitedpartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_5f543b4e-dca4-471c-a3fd-aad3ded11e68" xlink:to="loc_are_LimitedpartnershipsMember_5d5b5d1c-a1db-4a17-ae25-853f77a98f40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_89015d40-1cd4-48f5-84f1-aa689f4b4cfc" xlink:href="are-20230331.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_5f543b4e-dca4-471c-a3fd-aad3ded11e68" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_89015d40-1cd4-48f5-84f1-aa689f4b4cfc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_e6ca8794-55f4-4802-8611-7f0c9c11bd62" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_e6ca8794-55f4-4802-8611-7f0c9c11bd62" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_e6ca8794-55f4-4802-8611-7f0c9c11bd62_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_e6ca8794-55f4-4802-8611-7f0c9c11bd62" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_e6ca8794-55f4-4802-8611-7f0c9c11bd62_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_0232e3af-ec58-4202-9d39-245a81bc71a6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_e6ca8794-55f4-4802-8611-7f0c9c11bd62" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_0232e3af-ec58-4202-9d39-245a81bc71a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_dd45f9c2-a86d-4045-b007-c45cec6265d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_0232e3af-ec58-4202-9d39-245a81bc71a6" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_dd45f9c2-a86d-4045-b007-c45cec6265d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3e0d6bc3-d6c6-434b-bacf-1addb31a1adc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_dd45f9c2-a86d-4045-b007-c45cec6265d5" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_3e0d6bc3-d6c6-434b-bacf-1addb31a1adc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_f1f82108-4e44-4735-9c40-2ccbd7ee970b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_dd45f9c2-a86d-4045-b007-c45cec6265d5" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_f1f82108-4e44-4735-9c40-2ccbd7ee970b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_49cb3ed8-9611-47db-9c0d-e772188b671f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_49cb3ed8-9611-47db-9c0d-e772188b671f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_49cb3ed8-9611-47db-9c0d-e772188b671f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_49cb3ed8-9611-47db-9c0d-e772188b671f" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_49cb3ed8-9611-47db-9c0d-e772188b671f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_bd9b7d72-8aff-4eae-8db3-955f057d6ed7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_49cb3ed8-9611-47db-9c0d-e772188b671f" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_bd9b7d72-8aff-4eae-8db3-955f057d6ed7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_4389906d-c86b-4667-96ea-75019f0ff194" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_bd9b7d72-8aff-4eae-8db3-955f057d6ed7" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_4389906d-c86b-4667-96ea-75019f0ff194" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_01b816cb-365d-4d13-a9e2-8d4c69d18e9d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_bd9b7d72-8aff-4eae-8db3-955f057d6ed7" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_01b816cb-365d-4d13-a9e2-8d4c69d18e9d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1a592a73-306f-4126-bb2e-ffdec133d64d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1a592a73-306f-4126-bb2e-ffdec133d64d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a592a73-306f-4126-bb2e-ffdec133d64d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1a592a73-306f-4126-bb2e-ffdec133d64d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_1a592a73-306f-4126-bb2e-ffdec133d64d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_567da5b6-fab2-4ca4-bc3b-425625f1baee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_1a592a73-306f-4126-bb2e-ffdec133d64d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_567da5b6-fab2-4ca4-bc3b-425625f1baee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_5d35eab2-2188-4528-ae47-7f2e131e4d01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_567da5b6-fab2-4ca4-bc3b-425625f1baee" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_5d35eab2-2188-4528-ae47-7f2e131e4d01" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_4b7d05ee-231c-4c0c-9b5f-26cf335a319c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_567da5b6-fab2-4ca4-bc3b-425625f1baee" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_4b7d05ee-231c-4c0c-9b5f-26cf335a319c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_8ad8b4dd-5c9d-4638-b0f9-03fe3fda0d18" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_567da5b6-fab2-4ca4-bc3b-425625f1baee" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_8ad8b4dd-5c9d-4638-b0f9-03fe3fda0d18" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_c28d3509-dd95-4b98-ae52-733465993ef8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_c28d3509-dd95-4b98-ae52-733465993ef8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_c28d3509-dd95-4b98-ae52-733465993ef8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c28d3509-dd95-4b98-ae52-733465993ef8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_c28d3509-dd95-4b98-ae52-733465993ef8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_5114afbc-87f5-4f93-a6e2-1466804a34e6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_c28d3509-dd95-4b98-ae52-733465993ef8" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_5114afbc-87f5-4f93-a6e2-1466804a34e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A22BillionUnsecuredSeniorLineOfCreditMember_c832f76e-3aa4-49ed-8f07-00084cd4aafa" xlink:href="are-20230331.xsd#are_A22BillionUnsecuredSeniorLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_5114afbc-87f5-4f93-a6e2-1466804a34e6" xlink:to="loc_are_A22BillionUnsecuredSeniorLineOfCreditMember_c832f76e-3aa4-49ed-8f07-00084cd4aafa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_1aaeff5a-429e-425f-882b-bd20d0a6524a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_20fc2a1e-3153-497e-9ee5-16f5e1342483" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_1aaeff5a-429e-425f-882b-bd20d0a6524a" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_1aaeff5a-429e-425f-882b-bd20d0a6524a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_1aaeff5a-429e-425f-882b-bd20d0a6524a" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_1aaeff5a-429e-425f-882b-bd20d0a6524a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_d13f244b-52c2-4501-b43a-e815972de91d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_1aaeff5a-429e-425f-882b-bd20d0a6524a" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_d13f244b-52c2-4501-b43a-e815972de91d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_0003f315-4e3a-40cc-938e-6fd6dcd9ab82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_d13f244b-52c2-4501-b43a-e815972de91d" xlink:to="loc_us-gaap_CommercialPaperMember_0003f315-4e3a-40cc-938e-6fd6dcd9ab82" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/DetailofsecuredandunsecureddebtDetails" xlink:type="simple" xlink:href="are-20230331.xsd#DetailofsecuredandunsecureddebtDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/DetailofsecuredandunsecureddebtDetails" xlink:type="extended" id="i93810039aac2425b970f24e66c630daa_DetailofsecuredandunsecureddebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_7451d362-edf0-4f94-822e-f1c56fed9355" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_7451d362-edf0-4f94-822e-f1c56fed9355" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cd7870e5-ab57-4ef4-9c9f-bcab48c74bc3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_cd7870e5-ab57-4ef4-9c9f-bcab48c74bc3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_037e267b-0bc3-49dd-85a7-81897d04f085" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_037e267b-0bc3-49dd-85a7-81897d04f085" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_0d538503-d205-49fc-a95d-99c04d220295" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_0d538503-d205-49fc-a95d-99c04d220295" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_3f1d83e9-7285-45d0-9fb7-7a3bd44aaba4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_3f1d83e9-7285-45d0-9fb7-7a3bd44aaba4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBorrowingCapacity_c0807ca5-fd0b-4645-adef-83644fa78ec3" xlink:href="are-20230331.xsd#are_DebtInstrumentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_are_DebtInstrumentBorrowingCapacity_c0807ca5-fd0b-4645-adef-83644fa78ec3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtByMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_3ffd6393-0d49-4818-8259-e9762340a343" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_3ffd6393-0d49-4818-8259-e9762340a343" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_c76df168-65da-424b-ab30-3cd259a252d8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_c76df168-65da-424b-ab30-3cd259a252d8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_3df68577-c5f6-41ca-85cb-91b258babe10" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_3df68577-c5f6-41ca-85cb-91b258babe10" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_fb6521cd-d4b9-4489-b839-ab393fdd5d64" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_fb6521cd-d4b9-4489-b839-ab393fdd5d64" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_cc07ca8f-142f-4e79-9ec5-61ed373a411e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_cc07ca8f-142f-4e79-9ec5-61ed373a411e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_709643cc-25ef-441b-9c38-e074733e353e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_709643cc-25ef-441b-9c38-e074733e353e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_ec3e90a5-8ab3-45d4-b89c-7b13558b28df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_ec3e90a5-8ab3-45d4-b89c-7b13558b28df" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_9f305ec8-4ba1-4711-a288-d3e85eca4889" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_9f305ec8-4ba1-4711-a288-d3e85eca4889" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_cbb32513-296d-466d-ac36-06d0de7ac404" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_cae3b77e-aa97-4708-b4fa-5853dc03ac49" xlink:to="loc_us-gaap_LongTermDebt_cbb32513-296d-466d-ac36-06d0de7ac404" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_b2a8f2fa-c0bf-4120-ad13-8e3f875f2045" xlink:to="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_d70c7543-90ca-4e80-b04c-2db7f27fdbba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:to="loc_us-gaap_VariableRateAxis_d70c7543-90ca-4e80-b04c-2db7f27fdbba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_d70c7543-90ca-4e80-b04c-2db7f27fdbba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_d70c7543-90ca-4e80-b04c-2db7f27fdbba" xlink:to="loc_us-gaap_VariableRateDomain_d70c7543-90ca-4e80-b04c-2db7f27fdbba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_aeb79a42-d2d4-4f28-8c1f-463c2e08ac90" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_d70c7543-90ca-4e80-b04c-2db7f27fdbba" xlink:to="loc_us-gaap_VariableRateDomain_aeb79a42-d2d4-4f28-8c1f-463c2e08ac90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_de7197c3-11f3-4d1f-983d-3d4ec588093e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_aeb79a42-d2d4-4f28-8c1f-463c2e08ac90" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_de7197c3-11f3-4d1f-983d-3d4ec588093e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_a9348ba6-8464-4b62-a1c2-aab013687b47" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_a9348ba6-8464-4b62-a1c2-aab013687b47" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_a9348ba6-8464-4b62-a1c2-aab013687b47_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a9348ba6-8464-4b62-a1c2-aab013687b47" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_a9348ba6-8464-4b62-a1c2-aab013687b47_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_3d2dc6a9-0b5a-48ad-aea1-ec3e8142619e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_a9348ba6-8464-4b62-a1c2-aab013687b47" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_3d2dc6a9-0b5a-48ad-aea1-ec3e8142619e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_0a969d70-5e3d-4586-823e-ebb059abff7a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_3d2dc6a9-0b5a-48ad-aea1-ec3e8142619e" xlink:to="loc_us-gaap_CommercialPaperMember_0a969d70-5e3d-4586-823e-ebb059abff7a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b1e05996-007a-40c1-9f55-5d57373f122f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_e4f98b5f-e09e-466a-8c3c-fe4fac1c6e00" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b1e05996-007a-40c1-9f55-5d57373f122f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_e1da25e4-8cfa-4e81-8806-8865cbaf817f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b1e05996-007a-40c1-9f55-5d57373f122f" xlink:to="loc_us-gaap_SecuredDebtMember_e1da25e4-8cfa-4e81-8806-8865cbaf817f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecuredNotesPayableMaturingOn111926Member_101042bf-4b31-4211-a4e8-439f52fef120" xlink:href="are-20230331.xsd#are_SecuredNotesPayableMaturingOn111926Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SecuredDebtMember_e1da25e4-8cfa-4e81-8806-8865cbaf817f" xlink:to="loc_are_SecuredNotesPayableMaturingOn111926Member_101042bf-4b31-4211-a4e8-439f52fef120" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecuredNotesPayableMaturingJuly12036Member_72a13a76-9730-4982-ab1d-693d52eec9cc" xlink:href="are-20230331.xsd#are_SecuredNotesPayableMaturingJuly12036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SecuredDebtMember_e1da25e4-8cfa-4e81-8806-8865cbaf817f" xlink:to="loc_are_SecuredNotesPayableMaturingJuly12036Member_72a13a76-9730-4982-ab1d-693d52eec9cc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnsecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_b1e05996-007a-40c1-9f55-5d57373f122f" xlink:to="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_2c0cb756-e3bb-4ad0-ae37-a968b21e4284" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_us-gaap_LineOfCreditMember_2c0cb756-e3bb-4ad0-ae37-a968b21e4284" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.45unsecuredseniornotespayableduein2025Member_3fb2d88a-fb6a-4ec4-ac9e-830271263154" xlink:href="are-20230331.xsd#are_A3.45unsecuredseniornotespayableduein2025Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A3.45unsecuredseniornotespayableduein2025Member_3fb2d88a-fb6a-4ec4-ac9e-830271263154" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.30UnsecuredSeniorNotesPayableMember_291c00f2-b22a-423c-8415-e39b98516681" xlink:href="are-20230331.xsd#are_A4.30UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A4.30UnsecuredSeniorNotesPayableMember_291c00f2-b22a-423c-8415-e39b98516681" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.80UnsecuredSeniorNotesPayableMember_f1031839-18fe-4a3e-9732-b44b325f4775" xlink:href="are-20230331.xsd#are_A3.80UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A3.80UnsecuredSeniorNotesPayableMember_f1031839-18fe-4a3e-9732-b44b325f4775" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.95UnsecuredSeniorNotesPayableMember_9622c9a8-e850-4aff-9e12-0aea3a74578f" xlink:href="are-20230331.xsd#are_A3.95UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A3.95UnsecuredSeniorNotesPayableMember_9622c9a8-e850-4aff-9e12-0aea3a74578f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.95UnsecuredSeniorNotesPayableDuein2028Member_6eba2c67-4ed3-42b9-b715-5bd5e0121ddf" xlink:href="are-20230331.xsd#are_A3.95UnsecuredSeniorNotesPayableDuein2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A3.95UnsecuredSeniorNotesPayableDuein2028Member_6eba2c67-4ed3-42b9-b715-5bd5e0121ddf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_UnsecuredSeniorNotesDueinJuly2029Member_49bc8758-387c-4885-9098-e43d9214644b" xlink:href="are-20230331.xsd#are_UnsecuredSeniorNotesDueinJuly2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_UnsecuredSeniorNotesDueinJuly2029Member_49bc8758-387c-4885-9098-e43d9214644b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A2.75UnsecuredSeniorNotesPayableDue2029Member_1a9b1cac-5f5e-40c5-af71-276c9bff200c" xlink:href="are-20230331.xsd#are_A2.75UnsecuredSeniorNotesPayableDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A2.75UnsecuredSeniorNotesPayableDue2029Member_1a9b1cac-5f5e-40c5-af71-276c9bff200c" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.70UnsecuredSeniorNotesPayableMember_ad2f7a6b-ffa0-429b-966f-578de9f7b72d" xlink:href="are-20230331.xsd#are_A4.70UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A4.70UnsecuredSeniorNotesPayableMember_ad2f7a6b-ffa0-429b-966f-578de9f7b72d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.90UnsecuredSeniorNotesPayableMember_12c1e151-288c-407d-a12c-6c6e5f034148" xlink:href="are-20230331.xsd#are_A4.90UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A4.90UnsecuredSeniorNotesPayableMember_12c1e151-288c-407d-a12c-6c6e5f034148" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.375UnsecuredSeniorNotesPayableMember_d6bd1f54-8d63-49b7-bcfc-ce18ab245d44" xlink:href="are-20230331.xsd#are_A3.375UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A3.375UnsecuredSeniorNotesPayableMember_d6bd1f54-8d63-49b7-bcfc-ce18ab245d44" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A200UnsecuredSeniorNotesPayableMember_36a20237-36af-4515-b14b-916d0eb9b13a" xlink:href="are-20230331.xsd#are_A200UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A200UnsecuredSeniorNotesPayableMember_36a20237-36af-4515-b14b-916d0eb9b13a" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1875UnsecuredSeniorNotesPayableMember_e6d496f5-54c9-42e8-9e5d-a02fbe147b79" xlink:href="are-20230331.xsd#are_A1875UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A1875UnsecuredSeniorNotesPayableMember_e6d496f5-54c9-42e8-9e5d-a02fbe147b79" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A295UnsecuredSeniorNotesPayableMember_e41970eb-20b7-428f-9758-9c9f3cce87f3" xlink:href="are-20230331.xsd#are_A295UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A295UnsecuredSeniorNotesPayableMember_e41970eb-20b7-428f-9758-9c9f3cce87f3" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A475UnsecuredSeniorNotesPayableMember_d5e0b933-0554-4fdf-a133-f13a196762af" xlink:href="are-20230331.xsd#are_A475UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A475UnsecuredSeniorNotesPayableMember_d5e0b933-0554-4fdf-a133-f13a196762af" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.85UnsecuredSeniorNotePayableMember_2adb9688-2173-44c4-8a36-8e6070459ed6" xlink:href="are-20230331.xsd#are_A4.85UnsecuredSeniorNotePayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A4.85UnsecuredSeniorNotePayableMember_2adb9688-2173-44c4-8a36-8e6070459ed6" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.00UnsecuredSeniorNotesPayablesDue2050Member_6f37b1fc-9833-4bbd-8917-ebe5229d47fe" xlink:href="are-20230331.xsd#are_A4.00UnsecuredSeniorNotesPayablesDue2050Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A4.00UnsecuredSeniorNotesPayablesDue2050Member_6f37b1fc-9833-4bbd-8917-ebe5229d47fe" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A300UnsecuredSeniorNotesPayableMember_9f3cfaac-2225-470d-bf5e-28b935440c6e" xlink:href="are-20230331.xsd#are_A300UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A300UnsecuredSeniorNotesPayableMember_9f3cfaac-2225-470d-bf5e-28b935440c6e" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A355UnsecuredSeniorNotesPayableMember_bc7ee5c6-862b-4017-ba56-a2ceba007cb2" xlink:href="are-20230331.xsd#are_A355UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A355UnsecuredSeniorNotesPayableMember_bc7ee5c6-862b-4017-ba56-a2ceba007cb2" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A515UnsecuredSeniorNotesPayableMember_9f42dde9-2ee3-4851-a5c0-af573eb7385f" xlink:href="are-20230331.xsd#are_A515UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_2f72d8af-f2e7-41cf-97fb-a2d429c43c3e" xlink:to="loc_are_A515UnsecuredSeniorNotesPayableMember_9f42dde9-2ee3-4851-a5c0-af573eb7385f" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_87285b3f-60b6-4808-ac25-2346fb733664" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_c5572a6b-281e-4c7e-9fe6-f4ba1bf35777" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_87285b3f-60b6-4808-ac25-2346fb733664" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A99CoolidgeAvenueMember_01e0c553-fe50-4eb4-bcf5-8741f579537e" xlink:href="are-20230331.xsd#are_A99CoolidgeAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_87285b3f-60b6-4808-ac25-2346fb733664" xlink:to="loc_are_A99CoolidgeAvenueMember_01e0c553-fe50-4eb4-bcf5-8741f579537e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_8ad565fe-e584-4cc7-8b3e-168d4699cf0a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_b5641be6-63e6-40d3-9c8f-8a515e778d5c" xlink:to="loc_srt_OwnershipAxis_8ad565fe-e584-4cc7-8b3e-168d4699cf0a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_8ad565fe-e584-4cc7-8b3e-168d4699cf0a_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_8ad565fe-e584-4cc7-8b3e-168d4699cf0a" xlink:to="loc_srt_OwnershipDomain_8ad565fe-e584-4cc7-8b3e-168d4699cf0a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_78e95dbe-ad1f-4280-9165-54c53e7b430d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_8ad565fe-e584-4cc7-8b3e-168d4699cf0a" xlink:to="loc_srt_OwnershipDomain_78e95dbe-ad1f-4280-9165-54c53e7b430d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaMember_7b14f285-59b6-4e38-bc14-c3f4fd10fb1c" xlink:href="are-20230331.xsd#are_AlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_78e95dbe-ad1f-4280-9165-54c53e7b430d" xlink:to="loc_are_AlexandriaMember_7b14f285-59b6-4e38-bc14-c3f4fd10fb1c" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SummaryofsecuredandunsecureddebtDetails" xlink:type="simple" xlink:href="are-20230331.xsd#SummaryofsecuredandunsecureddebtDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SummaryofsecuredandunsecureddebtDetails" xlink:type="extended" id="i58ba92b0f4ee49b984ccaba647662805_SummaryofsecuredandunsecureddebtDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LongtermDebtPercentageBearingFixedInterestAmountNet_3a4a41cf-de22-45a4-8e65-1544ea480a7f" xlink:href="are-20230331.xsd#are_LongtermDebtPercentageBearingFixedInterestAmountNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_LongtermDebtPercentageBearingFixedInterestAmountNet_3a4a41cf-de22-45a4-8e65-1544ea480a7f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LongtermDebtPercentageBearingVariableInterestAmountNet_3088c897-cb64-4425-9742-b11f0ded5c92" xlink:href="are-20230331.xsd#are_LongtermDebtPercentageBearingVariableInterestAmountNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_LongtermDebtPercentageBearingVariableInterestAmountNet_3088c897-cb64-4425-9742-b11f0ded5c92" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_68253ef8-7056-4d2f-b2bd-338f31fdee94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_us-gaap_LongTermDebt_68253ef8-7056-4d2f-b2bd-338f31fdee94" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentPercentageOfOutstandingBalance_f2848dfb-d6ee-461a-83c1-309c72dbb17d" xlink:href="are-20230331.xsd#are_DebtInstrumentPercentageOfOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_DebtInstrumentPercentageOfOutstandingBalance_f2848dfb-d6ee-461a-83c1-309c72dbb17d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_1cebb894-a60f-4faa-911f-92c1724efa9e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_1cebb894-a60f-4faa-911f-92c1724efa9e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentWeightedAverageRemainingPeriod_5a64f6c8-6568-4046-9629-e4759bf0fbff" xlink:href="are-20230331.xsd#are_DebtInstrumentWeightedAverageRemainingPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_DebtInstrumentWeightedAverageRemainingPeriod_5a64f6c8-6568-4046-9629-e4759bf0fbff" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance_bb84e85b-5152-40f0-8b7f-31544510f13c" xlink:href="are-20230331.xsd#are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance_bb84e85b-5152-40f0-8b7f-31544510f13c" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance_998f853e-8247-4640-9a6d-1c8d59e9f0bb" xlink:href="are-20230331.xsd#are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance_998f853e-8247-4640-9a6d-1c8d59e9f0bb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Weightedaverageyieldtomaturitycommercialpaper_f281d23e-0fae-4cc5-8576-49e3c836782d" xlink:href="are-20230331.xsd#are_Weightedaverageyieldtomaturitycommercialpaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_Weightedaverageyieldtomaturitycommercialpaper_f281d23e-0fae-4cc5-8576-49e3c836782d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_0e706aa9-a3de-407a-9446-69f3cbd8d433" xlink:href="are-20230331.xsd#are_WeightedAverageRemainingMaturityTermCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_0e706aa9-a3de-407a-9446-69f3cbd8d433" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_ee45885d-bebb-40cf-a46b-e9c1a256c540" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_dd54c268-dac4-46d0-911f-98cbdc18d396" xlink:to="loc_us-gaap_DebtInstrumentTable_ee45885d-bebb-40cf-a46b-e9c1a256c540" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_54071a60-b84b-4009-bdf1-3c24ddf42605" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ee45885d-bebb-40cf-a46b-e9c1a256c540" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_54071a60-b84b-4009-bdf1-3c24ddf42605" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_54071a60-b84b-4009-bdf1-3c24ddf42605_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_54071a60-b84b-4009-bdf1-3c24ddf42605" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_54071a60-b84b-4009-bdf1-3c24ddf42605_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_aa93b500-3ba5-4777-8250-146ecbe2a413" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_54071a60-b84b-4009-bdf1-3c24ddf42605" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_aa93b500-3ba5-4777-8250-146ecbe2a413" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebtMember_eae2ad4a-9143-4a10-a6bd-46feceaae5b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_aa93b500-3ba5-4777-8250-146ecbe2a413" xlink:to="loc_us-gaap_SecuredDebtMember_eae2ad4a-9143-4a10-a6bd-46feceaae5b6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_e0c49cb3-e240-4e75-80d8-be19a9203a25" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_aa93b500-3ba5-4777-8250-146ecbe2a413" xlink:to="loc_us-gaap_SeniorNotesMember_e0c49cb3-e240-4e75-80d8-be19a9203a25" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_aa51c856-0120-4612-a33b-c51046dad2ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_aa93b500-3ba5-4777-8250-146ecbe2a413" xlink:to="loc_us-gaap_LineOfCreditMember_aa51c856-0120-4612-a33b-c51046dad2ec" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_ace9e638-71cc-40db-bce6-67f0e39ea0ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_ee45885d-bebb-40cf-a46b-e9c1a256c540" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_ace9e638-71cc-40db-bce6-67f0e39ea0ed" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_ace9e638-71cc-40db-bce6-67f0e39ea0ed_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_ace9e638-71cc-40db-bce6-67f0e39ea0ed" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_ace9e638-71cc-40db-bce6-67f0e39ea0ed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_1052c750-6481-4e81-8003-e3556b32f5d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_ace9e638-71cc-40db-bce6-67f0e39ea0ed" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_1052c750-6481-4e81-8003-e3556b32f5d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_cb7e6f5b-77fb-4ea7-aa2f-e005a91c2d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_1052c750-6481-4e81-8003-e3556b32f5d4" xlink:to="loc_us-gaap_CommercialPaperMember_cb7e6f5b-77fb-4ea7-aa2f-e005a91c2d5e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/UnsecuredseniornotespayableLOCandcommercialpaperDetails" xlink:type="simple" xlink:href="are-20230331.xsd#UnsecuredseniornotespayableLOCandcommercialpaperDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/UnsecuredseniornotespayableLOCandcommercialpaperDetails" xlink:type="extended" id="i56f43370fef84108864d177ac6f860d5_UnsecuredseniornotespayableLOCandcommercialpaperDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Totalissuanceofunsecuredseniornotes_9cb6c0f9-bf48-460a-bd32-3be1d6d5349c" xlink:href="are-20230331.xsd#are_Totalissuanceofunsecuredseniornotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_Totalissuanceofunsecuredseniornotes_9cb6c0f9-bf48-460a-bd32-3be1d6d5349c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtWeightedAverageInterestRate_f19d5ec5-7159-4b40-b07e-4589cb0ebf4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtWeightedAverageInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtWeightedAverageInterestRate_f19d5ec5-7159-4b40-b07e-4589cb0ebf4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Weightedaveragematurityyears_b35d7a50-f749-462e-a6cc-be0086fca565" xlink:href="are-20230331.xsd#are_Weightedaveragematurityyears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_Weightedaveragematurityyears_b35d7a50-f749-462e-a6cc-be0086fca565" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_cd2f4e36-6e62-4e4a-abeb-2e444ab152c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_cd2f4e36-6e62-4e4a-abeb-2e444ab152c8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_52559a28-1ae9-4826-99f7-20212964bdad" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_52559a28-1ae9-4826-99f7-20212964bdad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_f63f07be-8df0-4cbe-8624-239da2da92dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_f63f07be-8df0-4cbe-8624-239da2da92dc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentInterestRateAdjustmentAmountMaximum_e1444d12-d067-4bcd-802a-7cb805fff811" xlink:href="are-20230331.xsd#are_DebtInstrumentInterestRateAdjustmentAmountMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_DebtInstrumentInterestRateAdjustmentAmountMaximum_e1444d12-d067-4bcd-802a-7cb805fff811" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum_d291178c-71f2-4fcd-926f-009aa362b82b" xlink:href="are-20230331.xsd#are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum_d291178c-71f2-4fcd-926f-009aa362b82b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_182e8a17-bd0c-4a5f-b5a2-26e832f2bf83" xlink:href="are-20230331.xsd#are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_182e8a17-bd0c-4a5f-b5a2-26e832f2bf83" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease_66305cf0-afe5-4718-a646-a99f91fec5de" xlink:href="are-20230331.xsd#are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease_66305cf0-afe5-4718-a646-a99f91fec5de" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_9fdead64-d374-49a1-88de-c10a0626621a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_9fdead64-d374-49a1-88de-c10a0626621a" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_a429c5fe-a038-4297-b7e5-c4fd9e254bca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_a429c5fe-a038-4297-b7e5-c4fd9e254bca" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_51466bb9-52c2-4bf7-b94c-e6b2df191fcc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_LongTermDebt_51466bb9-52c2-4bf7-b94c-e6b2df191fcc" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommercialPaperMaximumIssuance_dd10823e-ad25-464d-86d0-9819a89d15b7" xlink:href="are-20230331.xsd#are_CommercialPaperMaximumIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_CommercialPaperMaximumIssuance_dd10823e-ad25-464d-86d0-9819a89d15b7" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_5fab14eb-992c-4ded-bdef-a27021bea6b8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtInstrumentTerm_5fab14eb-992c-4ded-bdef-a27021bea6b8" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Weightedaverageyieldtomaturitycommercialpaper_0c78d08f-ddde-4b92-be3f-2bd7678c0b59" xlink:href="are-20230331.xsd#are_Weightedaverageyieldtomaturitycommercialpaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_Weightedaverageyieldtomaturitycommercialpaper_0c78d08f-ddde-4b92-be3f-2bd7678c0b59" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_df06c428-1b57-4452-9a31-c42b58d597e4" xlink:href="are-20230331.xsd#are_WeightedAverageRemainingMaturityTermCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_df06c428-1b57-4452-9a31-c42b58d597e4" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_32368d37-d2cc-49db-be88-287e9f236013" xlink:to="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_b3ded065-cec9-4515-93b7-373f3277c84e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_b3ded065-cec9-4515-93b7-373f3277c84e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_b3ded065-cec9-4515-93b7-373f3277c84e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b3ded065-cec9-4515-93b7-373f3277c84e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_b3ded065-cec9-4515-93b7-373f3277c84e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_b3ded065-cec9-4515-93b7-373f3277c84e" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TotalIssuanceOfUnsecuredSeniorNotesInFeb2023Member_1b71c6a9-8873-4127-921b-4673b21428d3" xlink:href="are-20230331.xsd#are_TotalIssuanceOfUnsecuredSeniorNotesInFeb2023Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:to="loc_are_TotalIssuanceOfUnsecuredSeniorNotesInFeb2023Member_1b71c6a9-8873-4127-921b-4673b21428d3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A475UnsecuredSeniorNotesPayableMember_173718d6-5e85-45c7-bd87-f46d4397fc11" xlink:href="are-20230331.xsd#are_A475UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:to="loc_are_A475UnsecuredSeniorNotesPayableMember_173718d6-5e85-45c7-bd87-f46d4397fc11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A515UnsecuredSeniorNotesPayableMember_431f119b-950c-482b-9790-53677db28810" xlink:href="are-20230331.xsd#are_A515UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:to="loc_are_A515UnsecuredSeniorNotesPayableMember_431f119b-950c-482b-9790-53677db28810" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_d2f42e9b-e27e-4a24-9fa4-e18568d917f8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_046c34a3-8a0c-4412-9436-1c6f688fcb1e" xlink:to="loc_us-gaap_LineOfCreditMember_d2f42e9b-e27e-4a24-9fa4-e18568d917f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_f3612ede-5e40-4606-b142-ea17fd8a623a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_f3612ede-5e40-4606-b142-ea17fd8a623a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_f3612ede-5e40-4606-b142-ea17fd8a623a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_f3612ede-5e40-4606-b142-ea17fd8a623a" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_f3612ede-5e40-4606-b142-ea17fd8a623a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_3faad321-8653-4462-a5cb-3ea109cb0a90" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_f3612ede-5e40-4606-b142-ea17fd8a623a" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_3faad321-8653-4462-a5cb-3ea109cb0a90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_72407760-34ed-4130-a761-f6f9280e2cab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_3faad321-8653-4462-a5cb-3ea109cb0a90" xlink:to="loc_us-gaap_CommercialPaperMember_72407760-34ed-4130-a761-f6f9280e2cab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_1f8863ee-c12e-44cd-9897-56524fbd7d0e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:to="loc_us-gaap_VariableRateAxis_1f8863ee-c12e-44cd-9897-56524fbd7d0e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_1f8863ee-c12e-44cd-9897-56524fbd7d0e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_1f8863ee-c12e-44cd-9897-56524fbd7d0e" xlink:to="loc_us-gaap_VariableRateDomain_1f8863ee-c12e-44cd-9897-56524fbd7d0e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_350ed304-b5a1-4960-941c-22fcfec344bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_1f8863ee-c12e-44cd-9897-56524fbd7d0e" xlink:to="loc_us-gaap_VariableRateDomain_350ed304-b5a1-4960-941c-22fcfec344bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_a58173ec-9def-4a23-ad15-25a01bfcd5f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_350ed304-b5a1-4960-941c-22fcfec344bd" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_a58173ec-9def-4a23-ad15-25a01bfcd5f3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_5d6b43bc-dde3-4871-8832-1517f878b53d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_43c62dc0-e6ca-4d76-9f55-f72d8ecc5c08" xlink:to="loc_srt_RangeAxis_5d6b43bc-dde3-4871-8832-1517f878b53d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_5d6b43bc-dde3-4871-8832-1517f878b53d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_5d6b43bc-dde3-4871-8832-1517f878b53d" xlink:to="loc_srt_RangeMember_5d6b43bc-dde3-4871-8832-1517f878b53d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_767ba013-b9c1-4f53-801e-3e3900f3a35a" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_5d6b43bc-dde3-4871-8832-1517f878b53d" xlink:to="loc_srt_RangeMember_767ba013-b9c1-4f53-801e-3e3900f3a35a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_c11114ac-1360-4563-9cd0-16ad6793fdf9" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_767ba013-b9c1-4f53-801e-3e3900f3a35a" xlink:to="loc_srt_MaximumMember_c11114ac-1360-4563-9cd0-16ad6793fdf9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_e8e806f1-f0a2-469a-b3ba-b9f58071c55d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_767ba013-b9c1-4f53-801e-3e3900f3a35a" xlink:to="loc_srt_MinimumMember_e8e806f1-f0a2-469a-b3ba-b9f58071c55d" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails" xlink:type="simple" xlink:href="are-20230331.xsd#StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails" xlink:type="extended" id="icbd6eefb15104f04b533a85b797f5616_StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_458101d2-4374-4643-bc72-b35c2cfaa99a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_e435b319-1a03-4031-b696-f8d09d566b17" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_458101d2-4374-4643-bc72-b35c2cfaa99a" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_e435b319-1a03-4031-b696-f8d09d566b17" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Expectednetproceedsfromissuanceofcommonstock_6975c25f-35f2-4519-bbf3-3d6e1e1680a1" xlink:href="are-20230331.xsd#are_Expectednetproceedsfromissuanceofcommonstock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_458101d2-4374-4643-bc72-b35c2cfaa99a" xlink:to="loc_are_Expectednetproceedsfromissuanceofcommonstock_6975c25f-35f2-4519-bbf3-3d6e1e1680a1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommonStockValueAvailableForFutureIssuance_f999bcf9-cb40-4bd3-bb08-79b042cae354" xlink:href="are-20230331.xsd#are_CommonStockValueAvailableForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_458101d2-4374-4643-bc72-b35c2cfaa99a" xlink:to="loc_are_CommonStockValueAvailableForFutureIssuance_f999bcf9-cb40-4bd3-bb08-79b042cae354" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_92f0015c-4e24-4630-8a15-f73e3cd83de6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_458101d2-4374-4643-bc72-b35c2cfaa99a" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_92f0015c-4e24-4630-8a15-f73e3cd83de6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_f7d09508-c835-48e8-b944-476222eeb1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_92f0015c-4e24-4630-8a15-f73e3cd83de6" xlink:to="loc_us-gaap_PlanNameAxis_f7d09508-c835-48e8-b944-476222eeb1fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f7d09508-c835-48e8-b944-476222eeb1fc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_f7d09508-c835-48e8-b944-476222eeb1fc" xlink:to="loc_us-gaap_PlanNameDomain_f7d09508-c835-48e8-b944-476222eeb1fc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_ab3a97e1-3e75-4061-8db6-a24d02759e3e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_f7d09508-c835-48e8-b944-476222eeb1fc" xlink:to="loc_us-gaap_PlanNameDomain_ab3a97e1-3e75-4061-8db6-a24d02759e3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ATMCommonStockOfferingProgramEstablishedDecember2021Member_0c6d384a-6d5c-4c7d-bda4-e4c2a9be2af8" xlink:href="are-20230331.xsd#are_ATMCommonStockOfferingProgramEstablishedDecember2021Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_ab3a97e1-3e75-4061-8db6-a24d02759e3e" xlink:to="loc_are_ATMCommonStockOfferingProgramEstablishedDecember2021Member_0c6d384a-6d5c-4c7d-bda4-e4c2a9be2af8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis_5ce8054a-128b-4768-ae22-db6db289988b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_92f0015c-4e24-4630-8a15-f73e3cd83de6" xlink:to="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis_5ce8054a-128b-4768-ae22-db6db289988b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain_5ce8054a-128b-4768-ae22-db6db289988b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis_5ce8054a-128b-4768-ae22-db6db289988b" xlink:to="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain_5ce8054a-128b-4768-ae22-db6db289988b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain_214e90a3-1a70-4aac-b1aa-c3af030e01af" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeAxis_5ce8054a-128b-4768-ae22-db6db289988b" xlink:to="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain_214e90a3-1a70-4aac-b1aa-c3af030e01af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AllForwardEquitySalesAgreementsOutstandingMember_fc4eb573-c515-4120-930b-7f459d5077c5" xlink:href="are-20230331.xsd#are_AllForwardEquitySalesAgreementsOutstandingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ForwardContractIndexedToIssuersEquityTypeDomain_214e90a3-1a70-4aac-b1aa-c3af030e01af" xlink:to="loc_are_AllForwardEquitySalesAgreementsOutstandingMember_fc4eb573-c515-4120-930b-7f459d5077c5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/NoncontrollinginterestsDetails" xlink:type="simple" xlink:href="are-20230331.xsd#NoncontrollinginterestsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/NoncontrollinginterestsDetails" xlink:type="extended" id="ie70eadd6ff7944d0aeb057e1d829a7a7_NoncontrollinginterestsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestLineItems_4ab56e91-1602-4a64-b25d-f6fb6df37a8d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfRealEstatePropertiesSubjectToOwnershipFromNoncontrollingInterest_924bfa6a-38ba-4527-878c-6f9b1f16e0aa" xlink:href="are-20230331.xsd#are_NumberOfRealEstatePropertiesSubjectToOwnershipFromNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_4ab56e91-1602-4a64-b25d-f6fb6df37a8d" xlink:to="loc_are_NumberOfRealEstatePropertiesSubjectToOwnershipFromNoncontrollingInterest_924bfa6a-38ba-4527-878c-6f9b1f16e0aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_ace30467-93ad-486e-aa7f-579532f71561" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MinorityInterestLineItems_4ab56e91-1602-4a64-b25d-f6fb6df37a8d" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_ace30467-93ad-486e-aa7f-579532f71561" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestTable_7cf291df-e17b-4881-a40d-abc8401fbae4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_MinorityInterestLineItems_4ab56e91-1602-4a64-b25d-f6fb6df37a8d" xlink:to="loc_us-gaap_MinorityInterestTable_7cf291df-e17b-4881-a40d-abc8401fbae4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_7fa1e018-ac64-4713-b3e7-033c78e9293d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_MinorityInterestTable_7cf291df-e17b-4881-a40d-abc8401fbae4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_7fa1e018-ac64-4713-b3e7-033c78e9293d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_7fa1e018-ac64-4713-b3e7-033c78e9293d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_7fa1e018-ac64-4713-b3e7-033c78e9293d" xlink:to="loc_us-gaap_EquityComponentDomain_7fa1e018-ac64-4713-b3e7-033c78e9293d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_9522f3b0-9798-4c7f-811b-c0fb94aedbf7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_7fa1e018-ac64-4713-b3e7-033c78e9293d" xlink:to="loc_us-gaap_EquityComponentDomain_9522f3b0-9798-4c7f-811b-c0fb94aedbf7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_acb5514f-37ed-4691-b5f3-ed5de6731909" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_9522f3b0-9798-4c7f-811b-c0fb94aedbf7" xlink:to="loc_us-gaap_NoncontrollingInterestMember_acb5514f-37ed-4691-b5f3-ed5de6731909" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/AssetsclassifiedasheldforsaleDetails" xlink:type="simple" xlink:href="are-20230331.xsd#AssetsclassifiedasheldforsaleDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/AssetsclassifiedasheldforsaleDetails" xlink:type="extended" id="i57e174bd78454d1ead0c7beaefd5b2ce_AssetsclassifiedasheldforsaleDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_8b174652-a11d-4dbe-b62b-636c9f60a9d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfPropertiesHeldForSale_3756fc40-2659-4465-aa7e-61eb40c19cfe" xlink:href="are-20230331.xsd#are_NumberOfPropertiesHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_8b174652-a11d-4dbe-b62b-636c9f60a9d2" xlink:to="loc_are_NumberOfPropertiesHeldForSale_3756fc40-2659-4465-aa7e-61eb40c19cfe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAreaofRealEstate_7fdecf6d-d39d-4865-940f-8857e96c398a" xlink:href="are-20230331.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAreaofRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_8b174652-a11d-4dbe-b62b-636c9f60a9d2" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAreaofRealEstate_7fdecf6d-d39d-4865-940f-8857e96c398a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_8b174652-a11d-4dbe-b62b-636c9f60a9d2" xlink:to="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAssets_0c120c37-bbe5-46d6-80e4-e4bd3b432bcb" xlink:href="are-20230331.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAssets_0c120c37-bbe5-46d6-80e4-e4bd3b432bcb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsLiabilities_86a24968-55e0-458b-b72c-2b00b199eed0" xlink:href="are-20230331.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsLiabilities_86a24968-55e0-458b-b72c-2b00b199eed0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_42b72203-40f1-465f-ac05-69ce29575293" xlink:href="are-20230331.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_42b72203-40f1-465f-ac05-69ce29575293" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsNetAssets_2fa61fdb-34c8-4e7d-b498-a430aa8f1e6c" xlink:href="are-20230331.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsNetAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateHeldForDevelopmentAndSaleAbstract_5def89d7-c428-43c7-ac4b-94019cb500c5" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsNetAssets_2fa61fdb-34c8-4e7d-b498-a430aa8f1e6c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_69d1ccaf-f550-4318-8574-d18a2a559f5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_8b174652-a11d-4dbe-b62b-636c9f60a9d2" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_69d1ccaf-f550-4318-8574-d18a2a559f5c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_69d1ccaf-f550-4318-8574-d18a2a559f5c" xlink:to="loc_srt_StatementGeographicalAxis_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d" xlink:to="loc_srt_SegmentGeographicalDomain_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_961f3be7-2887-4e12-8eb7-0a451eb0bbaf" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_e246ce9a-e3f2-4d6d-bb67-57b8f6022b2d" xlink:to="loc_srt_SegmentGeographicalDomain_961f3be7-2887-4e12-8eb7-0a451eb0bbaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OthermarketsMember_eb141582-26c4-4aa3-8f43-916ed1c24a0d" xlink:href="are-20230331.xsd#are_OthermarketsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_961f3be7-2887-4e12-8eb7-0a451eb0bbaf" xlink:to="loc_are_OthermarketsMember_eb141582-26c4-4aa3-8f43-916ed1c24a0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NonCoreSubmarketMember_0b4c8f87-c444-44a4-9fec-638a5ff85b0d" xlink:href="are-20230331.xsd#are_NonCoreSubmarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_961f3be7-2887-4e12-8eb7-0a451eb0bbaf" xlink:to="loc_are_NonCoreSubmarketMember_0b4c8f87-c444-44a4-9fec-638a5ff85b0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ChinaPropertiesMember_c27478e6-cbb5-442d-a6a0-ec38577c8cb1" xlink:href="are-20230331.xsd#are_ChinaPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_961f3be7-2887-4e12-8eb7-0a451eb0bbaf" xlink:to="loc_are_ChinaPropertiesMember_c27478e6-cbb5-442d-a6a0-ec38577c8cb1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SubsequenteventsDetails" xlink:type="simple" xlink:href="are-20230331.xsd#SubsequenteventsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SubsequenteventsDetails" xlink:type="extended" id="i7565737114ef47b5a4cc41dba00e2d2e_SubsequenteventsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_92ac6397-52d7-4abe-a156-83cb8ce7b10d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_92ac6397-52d7-4abe-a156-83cb8ce7b10d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_4d9b6687-cb34-4012-b0dc-e9e2f7198ee9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_4d9b6687-cb34-4012-b0dc-e9e2f7198ee9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_47844a91-8e8f-4760-b01e-20dd83138439" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners_47844a91-8e8f-4760-b01e-20dd83138439" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMinorityShareholders_09b75c8b-1a86-408c-b879-f9ea7b7ef0fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_ProceedsFromMinorityShareholders_09b75c8b-1a86-408c-b879-f9ea7b7ef0fc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RealEstatePropertyOwnershipInterestSold_43c1c848-2878-4ee0-8337-01506b145db2" xlink:href="are-20230331.xsd#are_RealEstatePropertyOwnershipInterestSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_are_RealEstatePropertyOwnershipInterestSold_43c1c848-2878-4ee0-8337-01506b145db2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RealEstatePropertyOwnershipInterestSoldByNoncontrollingInterests_e60b3d54-0de8-48c2-af06-d33ecef91b9d" xlink:href="are-20230331.xsd#are_RealEstatePropertyOwnershipInterestSoldByNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_are_RealEstatePropertyOwnershipInterestSoldByNoncontrollingInterests_e60b3d54-0de8-48c2-af06-d33ecef91b9d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_9dfb265d-1126-4eb3-9a58-0ab3c4aead80" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_9dfb265d-1126-4eb3-9a58-0ab3c4aead80" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageRemainingLeaseTerm_3a46171f-a37d-481e-bf32-ffa690c85359" xlink:href="are-20230331.xsd#are_WeightedAverageRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_are_WeightedAverageRemainingLeaseTerm_3a46171f-a37d-481e-bf32-ffa690c85359" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfRealEstate_2bc443d8-5f9b-4040-8a59-1c492dc1e0a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ImpairmentOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_ImpairmentOfRealEstate_2bc443d8-5f9b-4040-8a59-1c492dc1e0a7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestments_c25ff1ac-8d5b-493f-bfdb-c363722e4890" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RealEstateInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_RealEstateInvestments_c25ff1ac-8d5b-493f-bfdb-c363722e4890" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_dec32fa4-6264-4a07-87da-3b48ea95e96d" xlink:href="are-20230331.xsd#are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_dec32fa4-6264-4a07-87da-3b48ea95e96d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_3a34eba5-1e18-46b9-b9bd-786991956de3" xlink:to="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_bb60282b-b516-4354-bc66-9e20a5e46676" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_bb60282b-b516-4354-bc66-9e20a5e46676" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_bb60282b-b516-4354-bc66-9e20a5e46676_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_bb60282b-b516-4354-bc66-9e20a5e46676" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_bb60282b-b516-4354-bc66-9e20a5e46676_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_10bc334b-0db5-4458-ba85-816bcb002acd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_bb60282b-b516-4354-bc66-9e20a5e46676" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_10bc334b-0db5-4458-ba85-816bcb002acd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_9e5c119b-7e8e-44ac-a09b-3a11867c3f85" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_10bc334b-0db5-4458-ba85-816bcb002acd" xlink:to="loc_us-gaap_SubsequentEventMember_9e5c119b-7e8e-44ac-a09b-3a11867c3f85" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8cb32957-ad22-4d27-ac52-fc54dbf9f91b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8cb32957-ad22-4d27-ac52-fc54dbf9f91b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8cb32957-ad22-4d27-ac52-fc54dbf9f91b_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8cb32957-ad22-4d27-ac52-fc54dbf9f91b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_8cb32957-ad22-4d27-ac52-fc54dbf9f91b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_11a96ef7-7706-4363-9dd3-6054b4e59309" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_8cb32957-ad22-4d27-ac52-fc54dbf9f91b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_11a96ef7-7706-4363-9dd3-6054b4e59309" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A15NeccoStreetMember_3d95b399-5091-49d0-90a9-f20c20cdc3ab" xlink:href="are-20230331.xsd#are_A15NeccoStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_11a96ef7-7706-4363-9dd3-6054b4e59309" xlink:to="loc_are_A15NeccoStreetMember_3d95b399-5091-49d0-90a9-f20c20cdc3ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A275GroveStreetMember_c3e0ace2-1fdd-4dff-8dce-80f7aba4ff78" xlink:href="are-20230331.xsd#are_A275GroveStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_11a96ef7-7706-4363-9dd3-6054b4e59309" xlink:to="loc_are_A275GroveStreetMember_c3e0ace2-1fdd-4dff-8dce-80f7aba4ff78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_5c1a21d8-c865-49f0-82ef-ab8e570506cd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_srt_OwnershipAxis_5c1a21d8-c865-49f0-82ef-ab8e570506cd" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_5c1a21d8-c865-49f0-82ef-ab8e570506cd_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_5c1a21d8-c865-49f0-82ef-ab8e570506cd" xlink:to="loc_srt_OwnershipDomain_5c1a21d8-c865-49f0-82ef-ab8e570506cd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_f7ac0696-527c-4940-b74b-e073b0009161" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_5c1a21d8-c865-49f0-82ef-ab8e570506cd" xlink:to="loc_srt_OwnershipDomain_f7ac0696-527c-4940-b74b-e073b0009161" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaMember_4cb5cfc8-2721-4a75-86ee-fd6461f3b283" xlink:href="are-20230331.xsd#are_AlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_f7ac0696-527c-4940-b74b-e073b0009161" xlink:to="loc_are_AlexandriaMember_4cb5cfc8-2721-4a75-86ee-fd6461f3b283" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba" xlink:to="loc_us-gaap_EquityComponentDomain_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_3f385f46-5375-4844-97e7-7ec23cfad0d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_b112d38b-8e6c-4f1f-b43f-8bf19ef5ffba" xlink:to="loc_us-gaap_EquityComponentDomain_3f385f46-5375-4844-97e7-7ec23cfad0d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_435f521f-4de8-4a08-a661-9a2a1cdf4324" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_3f385f46-5375-4844-97e7-7ec23cfad0d2" xlink:to="loc_us-gaap_NoncontrollingInterestMember_435f521f-4de8-4a08-a661-9a2a1cdf4324" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_fef31081-e7d7-42a9-adc2-e451f330e7d7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CounterpartyNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_srt_CounterpartyNameAxis_fef31081-e7d7-42a9-adc2-e451f330e7d7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fef31081-e7d7-42a9-adc2-e451f330e7d7_default" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CounterpartyNameAxis_fef31081-e7d7-42a9-adc2-e451f330e7d7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_fef31081-e7d7-42a9-adc2-e451f330e7d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac6eca26-6f50-4290-8b70-1f1e4bf408d5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CounterpartyNameAxis_fef31081-e7d7-42a9-adc2-e451f330e7d7" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac6eca26-6f50-4290-8b70-1f1e4bf408d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ExistingPartnerMember_94f3bf23-faae-4554-abba-4b102f125361" xlink:href="are-20230331.xsd#are_ExistingPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac6eca26-6f50-4290-8b70-1f1e4bf408d5" xlink:to="loc_are_ExistingPartnerMember_94f3bf23-faae-4554-abba-4b102f125361" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NewPartnerMember_cc6b367c-85c3-4d51-ba4a-40fe7a6c603a" xlink:href="are-20230331.xsd#are_NewPartnerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_ac6eca26-6f50-4290-8b70-1f1e4bf408d5" xlink:to="loc_are_NewPartnerMember_cc6b367c-85c3-4d51-ba4a-40fe7a6c603a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_17af18d4-a8e8-4b86-861e-9b28d6c61b86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_9b86b359-575e-40e1-b04b-acd7d34011c8" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_17af18d4-a8e8-4b86-861e-9b28d6c61b86" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_17af18d4-a8e8-4b86-861e-9b28d6c61b86_default" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_17af18d4-a8e8-4b86-861e-9b28d6c61b86" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_17af18d4-a8e8-4b86-861e-9b28d6c61b86_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_7c15b6da-1701-4cbd-b792-5137106b90ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_17af18d4-a8e8-4b86-861e-9b28d6c61b86" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_7c15b6da-1701-4cbd-b792-5137106b90ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_848b5044-1599-4b1e-9c35-4045887fc9f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_7c15b6da-1701-4cbd-b792-5137106b90ba" xlink:to="loc_us-gaap_LineOfCreditMember_848b5044-1599-4b1e-9c35-4045887fc9f6" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
