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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:019ead78-97d5-7bdc-b78a-6d942f9b622c,g:52572878-5f91-44c5-a288-0f08837b1391-->
<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-20260630.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedStatementsofOperations" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019ead78-99e8-75f6-b630-7eaba201db49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_StatementTable_019ead78-99e8-75f6-b630-7eaba201db49" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ead78-99e8-7150-86b8-c08c1ac99c0c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019ead78-99e8-75f6-b630-7eaba201db49" xlink:to="loc_srt_ProductOrServiceAxis_019ead78-99e8-7150-86b8-c08c1ac99c0c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7150-86b8-c08c1ac99c0c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e8-7150-86b8-c08c1ac99c0c" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7150-86b8-c08c1ac99c0c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7088-97e5-e0b1e92b8dad" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e8-7150-86b8-c08c1ac99c0c" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7088-97e5-e0b1e92b8dad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_019ead78-99e8-7a63-95cc-b1a1822fbed8" xlink:href="are-20260630.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7088-97e5-e0b1e92b8dad" xlink:to="loc_are_IncomefromrentalsMember_019ead78-99e8-7a63-95cc-b1a1822fbed8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_019ead78-99e8-7020-b804-bff042f58da5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-99e8-7088-97e5-e0b1e92b8dad" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_019ead78-99e8-7020-b804-bff042f58da5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-99e8-7b2b-998a-8be8dfdf1a16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-99e8-7b2b-998a-8be8dfdf1a16" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-99e8-719e-9b85-0a531a3a90e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-99e8-719e-9b85-0a531a3a90e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019ead78-99e8-774f-b147-e93913d7c683" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019ead78-99e8-774f-b147-e93913d7c683" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_019ead78-99e8-7c29-9db2-ae3e0c1dd27e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_InterestExpense_019ead78-99e8-7c29-9db2-ae3e0c1dd27e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_019ead78-99e8-7af9-be3e-41f7887a8219" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_DepreciationAndAmortization_019ead78-99e8-7af9-be3e-41f7887a8219" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfRealEstate_019ead78-99e8-7a35-aeaa-0996e6a2cd64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_ImpairmentOfRealEstate_019ead78-99e8-7a35-aeaa-0996e6a2cd64" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostsAndExpenses_019ead78-99e8-7978-994d-95b814a7fb83" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostsAndExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostsAndExpensesAbstract_019ead78-99e8-7112-a616-b2a96c2cd826" xlink:to="loc_us-gaap_CostsAndExpenses_019ead78-99e8-7978-994d-95b814a7fb83" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-99e8-706d-8a85-4901d66c6465" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-99e8-706d-8a85-4901d66c6465" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-99e8-757b-93d8-616b350090f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-99e8-757b-93d8-616b350090f3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-99e8-71c4-b826-7587763be0de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-99e8-71c4-b826-7587763be0de" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_019ead78-99e8-72ef-bb8a-f496b7dd99a5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_019ead78-99e8-72ef-bb8a-f496b7dd99a5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019ead78-99e8-7f5c-8308-28a9ae06fdc9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_ProfitLoss_019ead78-99e8-7f5c-8308-28a9ae06fdc9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019ead78-99e8-76b2-884f-856d512f1447" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_NetIncomeLossAttributableToNoncontrollingInterest_019ead78-99e8-76b2-884f-856d512f1447" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_019ead78-99e8-775a-872b-1568b43f7d20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_NetIncomeLoss_019ead78-99e8-775a-872b-1568b43f7d20" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted_019ead78-99e8-7e66-87b7-1108ad6e5b42" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_ParticipatingSecuritiesDistributedAndUndistributedEarningsLossDiluted_019ead78-99e8-7e66-87b7-1108ad6e5b42" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019ead78-99e8-7718-ba2e-fc1225c0a2d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_019ead78-99e8-7718-ba2e-fc1225c0a2d5" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_019ead78-99e8-76ed-b12f-185ca22bde89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_EarningsPerShareBasic_019ead78-99e8-76ed-b12f-185ca22bde89" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_019ead78-99e8-76b2-a7ba-c39779d79065" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7d51-a5b7-abf18e75cb02" xlink:to="loc_us-gaap_EarningsPerShareDiluted_019ead78-99e8-76b2-a7ba-c39779d79065" xlink:type="arc" order="12"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests" xlink:type="simple" xlink:href="are-20260630.xsd#ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedStatementofChangesinStockholdersEquityandNoncontrollingInterests" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_019ead78-99e8-7acb-a794-a2b00fe6a3fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_019ead78-99e8-71f3-8f8e-c6d697395ec2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7acb-a794-a2b00fe6a3fc" xlink:to="loc_us-gaap_StatementTable_019ead78-99e8-71f3-8f8e-c6d697395ec2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019ead78-99e8-7a0c-b7e3-7b9b0563e82e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_019ead78-99e8-71f3-8f8e-c6d697395ec2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019ead78-99e8-7a0c-b7e3-7b9b0563e82e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7a0c-b7e3-7b9b0563e82e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019ead78-99e8-7a0c-b7e3-7b9b0563e82e" xlink:to="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7a0c-b7e3-7b9b0563e82e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019ead78-99e8-7a0c-b7e3-7b9b0563e82e" xlink:to="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_019ead78-99e8-7441-a132-83d41695e35f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_us-gaap_CommonStockMember_019ead78-99e8-7441-a132-83d41695e35f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_019ead78-99e8-71c5-af6c-107c2e9c4645" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_019ead78-99e8-71c5-af6c-107c2e9c4645" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_019ead78-99e8-7c13-b94c-0159b37437be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_us-gaap_RetainedEarningsMember_019ead78-99e8-7c13-b94c-0159b37437be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019ead78-99e8-7e6f-b4e0-030c424cc770" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_019ead78-99e8-7e6f-b4e0-030c424cc770" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019ead78-99e8-7733-ad8d-6151e41bed63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019ead78-99e8-7733-ad8d-6151e41bed63" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RedeemableNoncontrollingInterestsMember_019ead78-99e8-792f-860d-8832f77890bd" xlink:href="are-20260630.xsd#are_RedeemableNoncontrollingInterestsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019ead78-99e8-7bab-97de-e38e1854088c" xlink:to="loc_are_RedeemableNoncontrollingInterestsMember_019ead78-99e8-792f-860d-8832f77890bd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7acb-a794-a2b00fe6a3fc" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019ead78-99e8-7873-bf7d-67593ec734bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_019ead78-99e8-7873-bf7d-67593ec734bc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ead78-99e8-730a-adea-dae2f57344be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ead78-99e8-730a-adea-dae2f57344be" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_019ead78-99e8-7ba1-9efa-c8e5c23abd0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_NetIncomeLossIncludingPortionAttributableToNonredeemableNoncontrollingInterest_019ead78-99e8-7ba1-9efa-c8e5c23abd0c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest_019ead78-99e8-70e5-add2-8e4236aeb09a" xlink:href="are-20260630.xsd#are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_are_OtherComprehensiveIncomeLossNetofTaxIncludingPortionAttributabletoNonredeemableNoncontrollingInterest_019ead78-99e8-70e5-add2-8e4236aeb09a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_019ead78-99e8-7628-96e9-0e7090276df5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromSaleOfParentEquityInterest_019ead78-99e8-7628-96e9-0e7090276df5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_019ead78-99e8-7dcf-84eb-c40a9ee50eb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders_019ead78-99e8-7dcf-84eb-c40a9ee50eb0" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019ead78-99e8-71e4-b82b-7dba624b95f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_019ead78-99e8-71e4-b82b-7dba624b95f1" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019ead78-99e8-7596-b827-a031b9e40aa7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_019ead78-99e8-7596-b827-a031b9e40aa7" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019ead78-99e8-7f6c-9c5f-ff02f440ebda" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_019ead78-99e8-7f6c-9c5f-ff02f440ebda" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019ead78-99e8-7541-8035-44686f36d1bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_019ead78-99e8-7541-8035-44686f36d1bd" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_019ead78-99e8-7619-a9ce-5986ceec2d08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_019ead78-99e8-7619-a9ce-5986ceec2d08" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_019ead78-99e8-7fe6-81ea-c5880cb3c76d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_019ead78-99e8-7fe6-81ea-c5880cb3c76d" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DividendsCommonStockCash_019ead78-99e9-7607-819c-1b060ad9f3ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DividendsCommonStockCash"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_DividendsCommonStockCash_019ead78-99e9-7607-819c-1b060ad9f3ce" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_019ead78-99e9-7e4a-b5c1-afe917a944a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_019ead78-99e8-7a04-9d35-d42311a52aab" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalDividendsInExcessOfRetainedEarnings_019ead78-99e9-7e4a-b5c1-afe917a944a1" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_019ead78-99e9-7e54-bb0d-70bedc76ec89" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_019ead78-99e9-7918-9999-bec7c152a3e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019ead78-99e9-7e00-b442-e44931e48343" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInTemporaryEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_019ead78-99e8-7acb-a794-a2b00fe6a3fc" xlink:to="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019ead78-99e9-7e00-b442-e44931e48343" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_019ead78-99e9-7332-95a3-0631690cb39a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019ead78-99e9-7e00-b442-e44931e48343" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_019ead78-99e9-7332-95a3-0631690cb39a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityNetIncome_019ead78-99e9-7d34-b7e6-d6708d53e998" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityNetIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019ead78-99e9-7e00-b442-e44931e48343" xlink:to="loc_us-gaap_TemporaryEquityNetIncome_019ead78-99e9-7d34-b7e6-d6708d53e998" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest_019ead78-99e9-766c-aac2-2229f37d1c02" xlink:href="are-20260630.xsd#are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInTemporaryEquityRollForward_019ead78-99e9-7e00-b442-e44931e48343" xlink:to="loc_are_TemporaryEquityDecreasefromDistributionstoNoncontrollingInterest_019ead78-99e9-766c-aac2-2229f37d1c02" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_019ead78-99e9-7bd4-97d5-8d6f1e946226" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/OrganizationandbasisofpresentationDetails" xlink:type="simple" xlink:href="are-20260630.xsd#OrganizationandbasisofpresentationDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/OrganizationandbasisofpresentationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7863-89a6-aa4db8bea6ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstatePropertiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-749f-a298-96c344b04b23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRealEstatePropertiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7863-89a6-aa4db8bea6ca" xlink:to="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-749f-a298-96c344b04b23" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019ead78-99e9-7626-a250-2b5b87cc95ad" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-749f-a298-96c344b04b23" xlink:to="loc_srt_StatementGeographicalAxis_019ead78-99e9-7626-a250-2b5b87cc95ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7626-a250-2b5b87cc95ad_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7626-a250-2b5b87cc95ad" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7626-a250-2b5b87cc95ad_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78d9-ba22-adc95f1826da" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7626-a250-2b5b87cc95ad" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78d9-ba22-adc95f1826da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019ead78-99e9-76cc-b506-0cc1bed2e8c5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78d9-ba22-adc95f1826da" xlink:to="loc_srt_NorthAmericaMember_019ead78-99e9-76cc-b506-0cc1bed2e8c5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019ead78-99e9-7e18-a293-3341edb53da5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-749f-a298-96c344b04b23" xlink:to="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019ead78-99e9-7e18-a293-3341edb53da5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7e18-a293-3341edb53da5_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019ead78-99e9-7e18-a293-3341edb53da5" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7e18-a293-3341edb53da5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7528-8777-735642d35fc8" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MortgageLoansOnRealEstateNamePropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis_019ead78-99e9-7e18-a293-3341edb53da5" xlink:to="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7528-8777-735642d35fc8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertiesMember_019ead78-99e9-72ad-821a-bbc2be8555ab" xlink:href="are-20260630.xsd#are_OperatingPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7528-8777-735642d35fc8" xlink:to="loc_are_OperatingPropertiesMember_019ead78-99e9-72ad-821a-bbc2be8555ab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ActiveDevelopmentRedevelopmentMember_019ead78-99e9-7b12-98b5-08a20bf2eefd" xlink:href="are-20260630.xsd#are_ActiveDevelopmentRedevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_MortgageLoansOnRealEstateNamePropertyTypeDomain_019ead78-99e9-7528-8777-735642d35fc8" xlink:to="loc_are_ActiveDevelopmentRedevelopmentMember_019ead78-99e9-7b12-98b5-08a20bf2eefd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_019ead78-99e9-7ee3-ad74-50201f50708d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7863-89a6-aa4db8bea6ca" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_019ead78-99e9-7ee3-ad74-50201f50708d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SummaryofsignificantaccountingpoliciesDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SummaryofsignificantaccountingpoliciesDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SummaryofsignificantaccountingpoliciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ead78-99e9-7580-b9ef-813ba4082ba3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:to="loc_srt_ProductOrServiceAxis_019ead78-99e9-7580-b9ef-813ba4082ba3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e9-7580-b9ef-813ba4082ba3_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e9-7580-b9ef-813ba4082ba3" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e9-7580-b9ef-813ba4082ba3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e9-76c8-acb9-c23656d2bd28" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e9-7580-b9ef-813ba4082ba3" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e9-76c8-acb9-c23656d2bd28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_019ead78-99e9-75ac-9b0c-461ea203983a" xlink:href="are-20260630.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-99e9-76c8-acb9-c23656d2bd28" xlink:to="loc_are_IncomefromrentalsMember_019ead78-99e9-75ac-9b0c-461ea203983a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_019ead78-99e9-7d5a-9012-84a508b2a56e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-99e9-76c8-acb9-c23656d2bd28" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_019ead78-99e9-7d5a-9012-84a508b2a56e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019ead78-99e9-7aac-bb1a-86d699ff90ef" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:to="loc_srt_StatementGeographicalAxis_019ead78-99e9-7aac-bb1a-86d699ff90ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7aac-bb1a-86d699ff90ef_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7aac-bb1a-86d699ff90ef" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7aac-bb1a-86d699ff90ef_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78f3-8c70-4602e9f66a79" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7aac-bb1a-86d699ff90ef" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78f3-8c70-4602e9f66a79" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_country_CA_019ead78-99e9-781c-96ce-36490b5a94b2" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_CA"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-99e9-78f3-8c70-4602e9f66a79" xlink:to="loc_country_CA_019ead78-99e9-781c-96ce-36490b5a94b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-99e9-70ec-8f04-f24f5a5150dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-99e9-70ec-8f04-f24f5a5150dc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-70ec-8f04-f24f5a5150dc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-99e9-70ec-8f04-f24f5a5150dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-70ec-8f04-f24f5a5150dc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-72cd-97fd-b51d6daa2f33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-99e9-70ec-8f04-f24f5a5150dc" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-72cd-97fd-b51d6daa2f33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandImprovementsMember_019ead78-99e9-7f2d-b892-a5d47200f186" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-72cd-97fd-b51d6daa2f33" xlink:to="loc_us-gaap_LandImprovementsMember_019ead78-99e9-7f2d-b892-a5d47200f186" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BuildingAndBuildingImprovementsMember_019ead78-99e9-7b48-9401-b6498f20c42e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BuildingAndBuildingImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-99e9-72cd-97fd-b51d6daa2f33" xlink:to="loc_us-gaap_BuildingAndBuildingImprovementsMember_019ead78-99e9-7b48-9401-b6498f20c42e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ead78-99e9-7c5d-bc40-564e8635ffe1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:to="loc_srt_RangeAxis_019ead78-99e9-7c5d-bc40-564e8635ffe1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-99e9-7c5d-bc40-564e8635ffe1_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ead78-99e9-7c5d-bc40-564e8635ffe1" xlink:to="loc_srt_RangeMember_019ead78-99e9-7c5d-bc40-564e8635ffe1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-99e9-70e3-b0b1-5af9ffed6bd0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ead78-99e9-7c5d-bc40-564e8635ffe1" xlink:to="loc_srt_RangeMember_019ead78-99e9-70e3-b0b1-5af9ffed6bd0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ead78-99e9-7010-9e99-b7be387a8c39" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ead78-99e9-70e3-b0b1-5af9ffed6bd0" xlink:to="loc_srt_MaximumMember_019ead78-99e9-7010-9e99-b7be387a8c39" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-715c-94ae-494c83cf4db6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_019ead78-99e9-7220-b430-6b6a38a39f60" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-715c-94ae-494c83cf4db6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-715c-94ae-494c83cf4db6_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-715c-94ae-494c83cf4db6" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-715c-94ae-494c83cf4db6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7591-85fd-b50344a97254" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-715c-94ae-494c83cf4db6" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7591-85fd-b50344a97254" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019ead78-99e9-73ce-8774-e7ac80b2c79a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7591-85fd-b50344a97254" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019ead78-99e9-73ce-8774-e7ac80b2c79a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019ead78-99e9-7cd6-9ee9-0c536f8a75ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_019ead78-99e9-7cd6-9ee9-0c536f8a75ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MaximumExpectedPeriodOfSaleOfProperty_019ead78-99e9-74d4-9d3e-8d33e0593d01" xlink:href="are-20260630.xsd#are_MaximumExpectedPeriodOfSaleOfProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_are_MaximumExpectedPeriodOfSaleOfProperty_019ead78-99e9-74d4-9d3e-8d33e0593d01" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-71b4-b8ec-4bbfca2b17c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-71b4-b8ec-4bbfca2b17c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CostMethodInvestmentOwnershipPercentage_019ead78-99e9-7a20-8c78-4362190cafde" xlink:href="are-20260630.xsd#are_CostMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_are_CostMethodInvestmentOwnershipPercentage_019ead78-99e9-7a20-8c78-4362190cafde" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_Percentageoftotalrevenues_019ead78-99e9-7f0c-8e09-499e2cfd32bf" xlink:href="are-20260630.xsd#are_Percentageoftotalrevenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_are_Percentageoftotalrevenues_019ead78-99e9-7f0c-8e09-499e2cfd32bf" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_019ead78-99e9-7776-aa34-6860e3814477" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_us-gaap_ContractWithCustomerAssetAccumulatedAllowanceForCreditLoss_019ead78-99e9-7776-aa34-6860e3814477" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MinimumPercentageOfTaxableIncomeToBeDistributed_019ead78-99e9-7abe-81cd-15ecf962ea81" xlink:href="are-20260630.xsd#are_MinimumPercentageOfTaxableIncomeToBeDistributed"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_are_MinimumPercentageOfTaxableIncomeToBeDistributed_019ead78-99e9-7abe-81cd-15ecf962ea81" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PercentOfTaxableIncomeGenerallyDistributedAsDividend_019ead78-99e9-76ec-9dbf-cef2291f3785" xlink:href="are-20260630.xsd#are_PercentOfTaxableIncomeGenerallyDistributedAsDividend"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_are_PercentOfTaxableIncomeGenerallyDistributedAsDividend_019ead78-99e9-76ec-9dbf-cef2291f3785" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenuesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_019ead78-99e9-78ac-b760-139b08f71a26" xlink:to="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_019ead78-99e9-7b38-a383-8e5766c16f39" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_019ead78-99e9-7b38-a383-8e5766c16f39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_019ead78-99e9-785f-85c2-fabecc842579" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_019ead78-99e9-785f-85c2-fabecc842579" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseIncome_019ead78-99e9-7daf-b783-ea1986576f20" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:to="loc_us-gaap_LeaseIncome_019ead78-99e9-7daf-b783-ea1986576f20" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_019ead78-99e9-72c1-a4d6-064092521e1a" xlink:href="are-20260630.xsd#are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:to="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_019ead78-99e9-72c1-a4d6-064092521e1a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-99e9-7157-a585-424aa5b4042e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesAbstract_019ead78-99e9-70b1-883d-d76b6dc9ff29" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-99e9-7157-a585-424aa5b4042e" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsinrealestateScheduleofinvestmentinrealestatesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateTable_019ead78-99e9-7b51-bf9e-02f7be4594a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RealEstateTable_019ead78-99e9-7b51-bf9e-02f7be4594a9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019ead78-99e9-7bb7-96c1-ecc8b8b27283" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_019ead78-99e9-7b51-bf9e-02f7be4594a9" xlink:to="loc_srt_StatementGeographicalAxis_019ead78-99e9-7bb7-96c1-ecc8b8b27283" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7bb7-96c1-ecc8b8b27283_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7bb7-96c1-ecc8b8b27283" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7bb7-96c1-ecc8b8b27283_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7b3a-8692-d235903e9696" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7bb7-96c1-ecc8b8b27283" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7b3a-8692-d235903e9696" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019ead78-99e9-7205-adf5-89a9fb40a1bc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7b3a-8692-d235903e9696" xlink:to="loc_srt_NorthAmericaMember_019ead78-99e9-7205-adf5-89a9fb40a1bc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7267-8f7c-3f37b69dfa4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RealEstateTable_019ead78-99e9-7b51-bf9e-02f7be4594a9" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7267-8f7c-3f37b69dfa4a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-7267-8f7c-3f37b69dfa4a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7267-8f7c-3f37b69dfa4a" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-7267-8f7c-3f37b69dfa4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-73cb-97fb-5f681bd1b3bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7267-8f7c-3f37b69dfa4a" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-73cb-97fb-5f681bd1b3bb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember_019ead78-99e9-7ab2-b816-b8d49031182a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-73cb-97fb-5f681bd1b3bb" xlink:to="loc_us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember_019ead78-99e9-7ab2-b816-b8d49031182a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Land_019ead78-99e9-7038-8b5d-4d2f37211371" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Land"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_Land_019ead78-99e9-7038-8b5d-4d2f37211371" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentBuildingAndBuildingImprovements_019ead78-99e9-7b2f-a49f-acb582aba430" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentBuildingAndBuildingImprovements"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_InvestmentBuildingAndBuildingImprovements_019ead78-99e9-7b2f-a49f-acb582aba430" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ImprovementsOthers_019ead78-99e9-7e1f-9776-11d5300da754" xlink:href="are-20260630.xsd#are_ImprovementsOthers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_are_ImprovementsOthers_019ead78-99e9-7e1f-9776-11d5300da754" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RentalProperties_019ead78-99e9-74d5-bd07-d4aa51ce9175" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RentalProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RentalProperties_019ead78-99e9-74d5-bd07-d4aa51ce9175" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DevelopmentInProcess_019ead78-99e9-7594-9419-5bed21a883e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DevelopmentInProcess"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_DevelopmentInProcess_019ead78-99e9-7594-9419-5bed21a883e3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost_019ead78-99e9-7b89-937a-04093804fbfc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAtCost_019ead78-99e9-7b89-937a-04093804fbfc" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_019ead78-99e9-7e7e-9c6b-a63f994d8069" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_019ead78-99e9-7e7e-9c6b-a63f994d8069" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7a4c-ac25-3600d68ce7eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7a4c-ac25-3600d68ce7eb" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestments_019ead78-99e9-75ff-b680-938ca6b7c02e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstateLineItems_019ead78-99e9-7f1f-859e-71e3c932fc5a" xlink:to="loc_us-gaap_RealEstateInvestments_019ead78-99e9-75ff-b680-938ca6b7c02e" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsinrealestateAssetsheldforsaleDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsinrealestateAssetsheldforsaleDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsinrealestateAssetsheldforsaleDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019ead78-99e9-7a08-9303-f882d03ee53b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019ead78-99e9-7a08-9303-f882d03ee53b" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7c28-98bb-636292affa36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019ead78-99e9-7a08-9303-f882d03ee53b" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7c28-98bb-636292affa36" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-7c28-98bb-636292affa36_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7c28-98bb-636292affa36" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-7c28-98bb-636292affa36_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-70ac-ab5c-3c0bee0dd2be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_019ead78-99e9-7c28-98bb-636292affa36" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-70ac-ab5c-3c0bee0dd2be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember_019ead78-99e9-70b8-9581-c2573ac85184" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_019ead78-99e9-70ac-ab5c-3c0bee0dd2be" xlink:to="loc_us-gaap_DisposalGroupHeldForSaleOrDisposedOfBySaleNotDiscontinuedOperationsMember_019ead78-99e9-70b8-9581-c2573ac85184" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeAxis_019ead78-99e9-77cc-991a-87476bf5391e" xlink:href="are-20260630.xsd#are_PropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019ead78-99e9-7a08-9303-f882d03ee53b" xlink:to="loc_are_PropertyTypeAxis_019ead78-99e9-77cc-991a-87476bf5391e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019ead78-99e9-77cc-991a-87476bf5391e_default" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PropertyTypeAxis_019ead78-99e9-77cc-991a-87476bf5391e" xlink:to="loc_are_PropertyTypeDomain_019ead78-99e9-77cc-991a-87476bf5391e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019ead78-99e9-7b5b-a02b-4240ddf696ef" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PropertyTypeAxis_019ead78-99e9-77cc-991a-87476bf5391e" xlink:to="loc_are_PropertyTypeDomain_019ead78-99e9-7b5b-a02b-4240ddf696ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertiesMember_019ead78-99e9-73d9-9a7e-1bf45207c3cf" xlink:href="are-20260630.xsd#are_OperatingPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019ead78-99e9-7b5b-a02b-4240ddf696ef" xlink:to="loc_are_OperatingPropertiesMember_019ead78-99e9-73d9-9a7e-1bf45207c3cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_019ead78-99e9-778d-bdbb-a54be2753bae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019ead78-99e9-7b5b-a02b-4240ddf696ef" xlink:to="loc_us-gaap_LandMember_019ead78-99e9-778d-bdbb-a54be2753bae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faef1-df9a-792a-bb1a-bf83e32ece60" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_019ead78-99e9-7a08-9303-f882d03ee53b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faef1-df9a-792a-bb1a-bf83e32ece60" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-792a-bb1a-bf83e32ece60_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faef1-df9a-792a-bb1a-bf83e32ece60" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-792a-bb1a-bf83e32ece60_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-7954-8830-52fd283bab33" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faef1-df9a-792a-bb1a-bf83e32ece60" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-7954-8830-52fd283bab33" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SanDiegoMarketMember_019faf5d-284a-71b2-9fcd-0536773bac26" xlink:href="are-20260630.xsd#are_SanDiegoMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-7954-8830-52fd283bab33" xlink:to="loc_are_SanDiegoMarketMember_019faf5d-284a-71b2-9fcd-0536773bac26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CanadaMarketMember_019faff6-0d9b-7f18-a76f-6d5796441526" xlink:href="are-20260630.xsd#are_CanadaMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faef1-df9a-7954-8830-52fd283bab33" xlink:to="loc_are_CanadaMarketMember_019faff6-0d9b-7f18-a76f-6d5796441526" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-7dde-b6ea-466629f04706" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-7dde-b6ea-466629f04706" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_019ead78-99e9-7848-9a6a-26a8ff52ea9f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_019ead78-99e9-7848-9a6a-26a8ff52ea9f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7f9e-8cae-af95ae2f7ecb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7f9e-8cae-af95ae2f7ecb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019ead78-99e9-79fe-9521-a79b224b690c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_OtherAssets_019ead78-99e9-79fe-9521-a79b224b690c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019ead78-99e9-7eaf-bac0-7b0fad008a5b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent_019ead78-99e9-7eaf-bac0-7b0fad008a5b" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019ead78-99e9-7265-acf6-8124d725e506" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_us-gaap_LiabilitiesOfDisposalGroupIncludingDiscontinuedOperationCurrent_019ead78-99e9-7265-acf6-8124d725e506" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_019ead78-99e9-7971-a71b-437e7cbf4c22" xlink:href="are-20260630.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_019ead78-99e9-7971-a71b-437e7cbf4c22" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldForSaleNotQualifyingAsDiscontinuedOperationsNetAssets_019ead78-99e9-7214-8539-3d4c1cc1afa7" xlink:href="are-20260630.xsd#are_DisposalGroupIncludingAssetsHeldForSaleNotQualifyingAsDiscontinuedOperationsNetAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_019ead78-99e9-7a7d-be42-4c09c903875c" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldForSaleNotQualifyingAsDiscontinuedOperationsNetAssets_019ead78-99e9-7214-8539-3d4c1cc1afa7" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsinrealestateSaleofRealEstateAssetsandImpairmentofRealEstateDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsinrealestateSaleofRealEstateAssetsandImpairmentofRealEstateDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsinrealestateSaleofRealEstateAssetsandImpairmentofRealEstateDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstatePropertiesLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRealEstatePropertiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faff9-1e80-7145-97f5-2048067304f1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faff9-1e80-7145-97f5-2048067304f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7145-97f5-2048067304f1_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faff9-1e80-7145-97f5-2048067304f1" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7145-97f5-2048067304f1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faff9-1e80-7145-97f5-2048067304f1" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OneHampshireStreetMember_019fb04a-a170-7d61-9d5f-3680547d9f26" xlink:href="are-20260630.xsd#are_OneHampshireStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_OneHampshireStreetMember_019fb04a-a170-7d61-9d5f-3680547d9f26" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A391139314025403140454075SorrentoValleyBlvdMember_019fb04c-38d6-74f3-91b8-5770a9e6688c" xlink:href="are-20260630.xsd#are_A391139314025403140454075SorrentoValleyBlvdMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_A391139314025403140454075SorrentoValleyBlvdMember_019fb04c-38d6-74f3-91b8-5770a9e6688c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A88BluxomeStreetMember_019fb04d-f8c0-7043-a8a7-e7de72710bbf" xlink:href="are-20260630.xsd#are_A88BluxomeStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_A88BluxomeStreetMember_019fb04d-f8c0-7043-a8a7-e7de72710bbf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3825And3875FabianWayMember_019faff9-1e80-7904-9205-07eb7fef2caa" xlink:href="are-20260630.xsd#are_A3825And3875FabianWayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_A3825And3875FabianWayMember_019faff9-1e80-7904-9205-07eb7fef2caa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A720BayStreetMember_019fb054-09c7-77f0-9f45-80a68d0ad93a" xlink:href="are-20260630.xsd#are_A720BayStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_A720BayStreetMember_019fb054-09c7-77f0-9f45-80a68d0ad93a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SanDiegoMarketMember_019faff9-4ebb-75db-81ba-c31c6933523c" xlink:href="are-20260630.xsd#are_SanDiegoMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_SanDiegoMarketMember_019faff9-4ebb-75db-81ba-c31c6933523c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MontrealPropertiesMember_019faff9-6f6b-7056-8641-c7a8311fd33f" xlink:href="are-20260630.xsd#are_MontrealPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_MontrealPropertiesMember_019faff9-6f6b-7056-8641-c7a8311fd33f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CanadaMarketMember_019faff9-6f6b-7e84-935c-ece3f0f6be49" xlink:href="are-20260630.xsd#are_CanadaMarketMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_CanadaMarketMember_019faff9-6f6b-7e84-935c-ece3f0f6be49" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaCenterForLifeScienceNewYorkCityMember_019fafff-11b3-7c5b-a24c-8ea1b4279392" xlink:href="are-20260630.xsd#are_AlexandriaCenterForLifeScienceNewYorkCityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faff9-1e80-7483-8cad-b82d9d8c643d" xlink:to="loc_are_AlexandriaCenterForLifeScienceNewYorkCityMember_019fafff-11b3-7c5b-a24c-8ea1b4279392" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeAxis_019faff9-1e80-700b-928e-012fe2dd9fd5" xlink:href="are-20260630.xsd#are_PropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:to="loc_are_PropertyTypeAxis_019faff9-1e80-700b-928e-012fe2dd9fd5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019faff9-1e80-700b-928e-012fe2dd9fd5_default" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PropertyTypeAxis_019faff9-1e80-700b-928e-012fe2dd9fd5" xlink:to="loc_are_PropertyTypeDomain_019faff9-1e80-700b-928e-012fe2dd9fd5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019faff9-1e80-73fe-971f-94332ea9cd24" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PropertyTypeAxis_019faff9-1e80-700b-928e-012fe2dd9fd5" xlink:to="loc_are_PropertyTypeDomain_019faff9-1e80-73fe-971f-94332ea9cd24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertiesMember_019faff9-1e80-7fe8-99c2-ebaec268e05b" xlink:href="are-20260630.xsd#are_OperatingPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019faff9-1e80-73fe-971f-94332ea9cd24" xlink:to="loc_are_OperatingPropertiesMember_019faff9-1e80-7fe8-99c2-ebaec268e05b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FutureDevelopmentProjectsMember_019faff9-1e80-7944-92a8-10311368aa18" xlink:href="are-20260630.xsd#are_FutureDevelopmentProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019faff9-1e80-73fe-971f-94332ea9cd24" xlink:to="loc_are_FutureDevelopmentProjectsMember_019faff9-1e80-7944-92a8-10311368aa18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandMember_019faff9-4ebb-736b-85a3-e8e3eaf3c3e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LandMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019faff9-1e80-73fe-971f-94332ea9cd24" xlink:to="loc_us-gaap_LandMember_019faff9-4ebb-736b-85a3-e8e3eaf3c3e8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019faff9-1e80-7046-89c4-702cc0cf1db1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:to="loc_srt_StatementGeographicalAxis_019faff9-1e80-7046-89c4-702cc0cf1db1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019faff9-1e80-7046-89c4-702cc0cf1db1_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019faff9-1e80-7046-89c4-702cc0cf1db1" xlink:to="loc_srt_SegmentGeographicalDomain_019faff9-1e80-7046-89c4-702cc0cf1db1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019faff9-1e80-7c93-a67e-7ddbbc32e154" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019faff9-1e80-7046-89c4-702cc0cf1db1" xlink:to="loc_srt_SegmentGeographicalDomain_019faff9-1e80-7c93-a67e-7ddbbc32e154" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019faff9-1e80-7585-9e64-d2a8c8fcc026" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019faff9-1e80-7c93-a67e-7ddbbc32e154" xlink:to="loc_srt_NorthAmericaMember_019faff9-1e80-7585-9e64-d2a8c8fcc026" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019faff9-6f6b-7728-a1e8-e073e606ba93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019faff9-6f6b-7728-a1e8-e073e606ba93" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019faff9-6f6b-7728-a1e8-e073e606ba93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019faff9-6f6b-7728-a1e8-e073e606ba93" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019faff9-6f6b-7728-a1e8-e073e606ba93_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019faff9-6f6b-75cf-ab50-74104c0d78a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019faff9-6f6b-7728-a1e8-e073e606ba93" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019faff9-6f6b-75cf-ab50-74104c0d78a2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019faff9-6f6b-73b8-9261-7d8f15c2e115" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019faff9-6f6b-75cf-ab50-74104c0d78a2" xlink:to="loc_us-gaap_SubsequentEventMember_019faff9-6f6b-73b8-9261-7d8f15c2e115" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseAxis_019fafff-11b3-7b0d-80ab-b432f1cf44da" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_LitigationCaseAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_019ead78-99e9-78dc-a9ef-b511d36f79e7" xlink:to="loc_srt_LitigationCaseAxis_019fafff-11b3-7b0d-80ab-b432f1cf44da" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_019fafff-11b3-7b0d-80ab-b432f1cf44da_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_LitigationCaseAxis_019fafff-11b3-7b0d-80ab-b432f1cf44da" xlink:to="loc_srt_LitigationCaseTypeDomain_019fafff-11b3-7b0d-80ab-b432f1cf44da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_LitigationCaseTypeDomain_019fafff-11b3-7cfb-b9a3-f12be047f562" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_LitigationCaseTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_LitigationCaseAxis_019fafff-11b3-7b0d-80ab-b432f1cf44da" xlink:to="loc_srt_LitigationCaseTypeDomain_019fafff-11b3-7cfb-b9a3-f12be047f562" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_HHAndEDCLitigationMember_019fafff-11b3-7c25-b2b5-1103bdb7d633" xlink:href="are-20260630.xsd#are_HHAndEDCLitigationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_LitigationCaseTypeDomain_019fafff-11b3-7cfb-b9a3-f12be047f562" xlink:to="loc_are_HHAndEDCLitigationMember_019fafff-11b3-7c25-b2b5-1103bdb7d633" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyHeldForSale_019faff9-1e80-7444-a856-f25f887c9926" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfPropertyHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyHeldForSale_019faff9-1e80-7444-a856-f25f887c9926" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RealEstatePropertyOwnershipInterestSold_019faff9-1e80-7c29-8e28-d442ad61972a" xlink:href="are-20260630.xsd#are_RealEstatePropertyOwnershipInterestSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_RealEstatePropertyOwnershipInterestSold_019faff9-1e80-7c29-8e28-d442ad61972a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_019faff9-1e80-725c-a934-11577e12a9a2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_019faff9-1e80-725c-a934-11577e12a9a2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfRealEstate_019faff9-4ebb-7e6a-b5b9-e37afb84c57a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_ImpairmentOfRealEstate_019faff9-4ebb-7e6a-b5b9-e37afb84c57a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PotentialAssetDispositionConsideration_019faff9-4ebb-7d63-a558-c44fe0b054a0" xlink:href="are-20260630.xsd#are_PotentialAssetDispositionConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_PotentialAssetDispositionConsideration_019faff9-4ebb-7d63-a558-c44fe0b054a0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_019faff9-4ebb-73fd-a760-6af75e39bdb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_019faff9-4ebb-73fd-a760-6af75e39bdb4" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ReversalOfImpairmentCharges_019faff9-6f6b-7fec-a6bd-27b84bc76335" xlink:href="are-20260630.xsd#are_ReversalOfImpairmentCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_ReversalOfImpairmentCharges_019faff9-6f6b-7fec-a6bd-27b84bc76335" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_019faff9-6f6b-7155-9a45-1770cc2fab27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_019faff9-6f6b-7155-9a45-1770cc2fab27" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_019faff9-6f6b-7f87-8382-6cd398b6713a" xlink:href="are-20260630.xsd#are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_DisposalGroupIncludingAssetsHeldforSaleNotQualifyingasDiscontinuedOperationsAccumulatedOtherComprehensiveIncomeLoss_019faff9-6f6b-7f87-8382-6cd398b6713a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAtCost_019fafff-11b3-76e2-9cac-6c1230802743" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyAtCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyAtCost_019fafff-11b3-76e2-9cac-6c1230802743" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ContingentAssetsSecurityDeposit_019fafff-11b3-7eda-885b-08d4608bef41" xlink:href="are-20260630.xsd#are_ContingentAssetsSecurityDeposit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_ContingentAssetsSecurityDeposit_019fafff-11b3-7eda-885b-08d4608bef41" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fafff-11b3-7db5-8545-337856784e72" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LossContingencyEstimateOfPossibleLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_us-gaap_LossContingencyEstimateOfPossibleLoss_019fafff-11b3-7db5-8545-337856784e72" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LossContingencyCurePeriod_019fafff-11b3-7c71-a7ff-f131dbea5313" xlink:href="are-20260630.xsd#are_LossContingencyCurePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_LossContingencyCurePeriod_019fafff-11b3-7c71-a7ff-f131dbea5313" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LossContingencyEstimateOfPossibleLossRangeDailyLowerLimit_019fafff-11b3-7e18-9030-e52cb9c8d6e0" xlink:href="are-20260630.xsd#are_LossContingencyEstimateOfPossibleLossRangeDailyLowerLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_LossContingencyEstimateOfPossibleLossRangeDailyLowerLimit_019fafff-11b3-7e18-9030-e52cb9c8d6e0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LossContingencyEstimateOfPossibleLossRangeDailyUpperLimit_019fafff-11b3-7c54-8b02-cb566aa6b260" xlink:href="are-20260630.xsd#are_LossContingencyEstimateOfPossibleLossRangeDailyUpperLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_019ead78-99e9-7ea6-a76c-cc8c0132e662" xlink:to="loc_are_LossContingencyEstimateOfPossibleLossRangeDailyUpperLimit_019fafff-11b3-7c54-8b02-cb566aa6b260" xlink:type="arc" order="14"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresDetails" xlink:type="simple" xlink:href="are-20260630.xsd#ConsolidatedandunconsolidatedrealestatejointventuresDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-75ff-a0d2-1ea2e3cf7995" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-77f2-919b-e4a6cb8fa2b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-75ff-a0d2-1ea2e3cf7995" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-77f2-919b-e4a6cb8fa2b0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7b63-8320-caae741a5399" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-77f2-919b-e4a6cb8fa2b0" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7b63-8320-caae741a5399" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7b63-8320-caae741a5399_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7b63-8320-caae741a5399" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7b63-8320-caae741a5399_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7b63-8320-caae741a5399" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A50And60BinneyStreetMember_019ead78-99e9-721f-8c82-f6456fdf66bb" xlink:href="are-20260630.xsd#are_A50And60BinneyStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A50And60BinneyStreetMember_019ead78-99e9-721f-8c82-f6456fdf66bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A75125BinneyStreetMember_019ead78-99e9-78a6-bce7-173e6f3f325a" xlink:href="are-20260630.xsd#are_A75125BinneyStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A75125BinneyStreetMember_019ead78-99e9-78a6-bce7-173e6f3f325a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A100And225BinneyStreetAnd300ThirdStreetMember_019ead78-99e9-7de8-919a-32bfae9b680d" xlink:href="are-20260630.xsd#are_A100And225BinneyStreetAnd300ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A100And225BinneyStreetAnd300ThirdStreetMember_019ead78-99e9-7de8-919a-32bfae9b680d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A15NeccoStreetMember_019ead78-99e9-7ed1-9843-51ee703d97e4" xlink:href="are-20260630.xsd#are_A15NeccoStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A15NeccoStreetMember_019ead78-99e9-7ed1-9843-51ee703d97e4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3215MerryfieldRowMember_019ead78-99e9-76ea-a8a4-cbe4a704bb68" xlink:href="are-20260630.xsd#are_A3215MerryfieldRowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A3215MerryfieldRowMember_019ead78-99e9-76ea-a8a4-cbe4a704bb68" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CampusPointByAlexandriaMember_019ead78-99e9-7e78-bc43-6c6c6e2f08ce" xlink:href="are-20260630.xsd#are_CampusPointByAlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_CampusPointByAlexandriaMember_019ead78-99e9-7e78-bc43-6c6c6e2f08ce" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5200IlluminaWayMember_019ead78-99e9-7c0d-a4e5-dcdca0325b93" xlink:href="are-20260630.xsd#are_A5200IlluminaWayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A5200IlluminaWayMember_019ead78-99e9-7c0d-a4e5-dcdca0325b93" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A9625TowneCentreDriveMember_019ead78-99e9-7b0d-84c1-b0bf13dd20b8" xlink:href="are-20260630.xsd#are_A9625TowneCentreDriveMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A9625TowneCentreDriveMember_019ead78-99e9-7b0d-84c1-b0bf13dd20b8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SDTechbyAlexandriaMember_019ead78-99e9-7107-a6ce-da158215bb77" xlink:href="are-20260630.xsd#are_SDTechbyAlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_SDTechbyAlexandriaMember_019ead78-99e9-7107-a6ce-da158215bb77" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SummersRidgeScienceParkMember_019ead78-99e9-7872-862e-8d3c9be88385" xlink:href="are-20260630.xsd#are_SummersRidgeScienceParkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_SummersRidgeScienceParkMember_019ead78-99e9-7872-862e-8d3c9be88385" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaCenterForScienceAndTechnologyMissionBayMember_019ead78-99e9-7c4f-b632-56ff504feb3b" xlink:href="are-20260630.xsd#are_AlexandriaCenterForScienceAndTechnologyMissionBayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_AlexandriaCenterForScienceAndTechnologyMissionBayMember_019ead78-99e9-7c4f-b632-56ff504feb3b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A211And213EastGrandAvenueMember_019ead78-99e9-7233-9165-50d92383bfd0" xlink:href="are-20260630.xsd#are_A211And213EastGrandAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A211And213EastGrandAvenueMember_019ead78-99e9-7233-9165-50d92383bfd0" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A500ForbesBoulevardMember_019ead78-99e9-7ab7-9a2b-433e02637295" xlink:href="are-20260630.xsd#are_A500ForbesBoulevardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A500ForbesBoulevardMember_019ead78-99e9-7ab7-9a2b-433e02637295" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaCenterForLifeScienceMillbraeMember_019ead78-99e9-7ee1-9226-620db4cb568d" xlink:href="are-20260630.xsd#are_AlexandriaCenterForLifeScienceMillbraeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_AlexandriaCenterForLifeScienceMillbraeMember_019ead78-99e9-7ee1-9226-620db4cb568d" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1201And1208EastlakeAvenueEastMember_019ead78-99e9-7c7b-8faf-72ab03ab821a" xlink:href="are-20260630.xsd#are_A1201And1208EastlakeAvenueEastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A1201And1208EastlakeAvenueEastMember_019ead78-99e9-7c7b-8faf-72ab03ab821a" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A400DexterAvenueNorthMember_019ead78-99e9-734f-9e63-6063f70116ba" xlink:href="are-20260630.xsd#are_A400DexterAvenueNorthMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A400DexterAvenueNorthMember_019ead78-99e9-734f-9e63-6063f70116ba" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A800MercerStreetMember_019ead78-99e9-71f6-a75f-f0243fa50382" xlink:href="are-20260630.xsd#are_A800MercerStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A800MercerStreetMember_019ead78-99e9-71f6-a75f-f0243fa50382" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A99CoolidgeAvenueMember_019ead78-99e9-73f1-8dae-4dac3d651b53" xlink:href="are-20260630.xsd#are_A99CoolidgeAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7bc4-a502-33195600cfbb" xlink:to="loc_are_A99CoolidgeAvenueMember_019ead78-99e9-73f1-8dae-4dac3d651b53" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-79ba-9b1d-af08c6e68849" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-77f2-919b-e4a6cb8fa2b0" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-79ba-9b1d-af08c6e68849" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-79ba-9b1d-af08c6e68849_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-79ba-9b1d-af08c6e68849" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-79ba-9b1d-af08c6e68849_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7aad-91a8-9e4d0acac049" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-79ba-9b1d-af08c6e68849" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7aad-91a8-9e4d0acac049" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1655And1725ThirdStreetMember_019ead78-99e9-798c-be90-6544f05cf11b" xlink:href="are-20260630.xsd#are_A1655And1725ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7aad-91a8-9e4d0acac049" xlink:to="loc_are_A1655And1725ThirdStreetMember_019ead78-99e9-798c-be90-6544f05cf11b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A101WestDickmanStreetMember_019ead78-99e9-768d-bf22-40653ba1242c" xlink:href="are-20260630.xsd#are_A101WestDickmanStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7aad-91a8-9e4d0acac049" xlink:to="loc_are_A101WestDickmanStreetMember_019ead78-99e9-768d-bf22-40653ba1242c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipAxis_019ead78-99e9-7a36-b169-bcd8af818bed" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-77f2-919b-e4a6cb8fa2b0" xlink:to="loc_srt_OwnershipAxis_019ead78-99e9-7a36-b169-bcd8af818bed" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019ead78-99e9-7a36-b169-bcd8af818bed_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_OwnershipAxis_019ead78-99e9-7a36-b169-bcd8af818bed" xlink:to="loc_srt_OwnershipDomain_019ead78-99e9-7a36-b169-bcd8af818bed_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_OwnershipDomain_019ead78-99e9-7a22-8b36-7277759872e2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_OwnershipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_OwnershipAxis_019ead78-99e9-7a36-b169-bcd8af818bed" xlink:to="loc_srt_OwnershipDomain_019ead78-99e9-7a22-8b36-7277759872e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaMember_019ead78-99e9-76cf-a40a-fc054a3ebc0d" xlink:href="are-20260630.xsd#are_AlexandriaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_OwnershipDomain_019ead78-99e9-7a22-8b36-7277759872e2" xlink:to="loc_are_AlexandriaMember_019ead78-99e9-76cf-a40a-fc054a3ebc0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019ead78-99e9-7a4e-9f0f-1e1e642dc3bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestOwnershipPercentageByParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-75ff-a0d2-1ea2e3cf7995" xlink:to="loc_us-gaap_MinorityInterestOwnershipPercentageByParent_019ead78-99e9-7a4e-9f0f-1e1e642dc3bd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019ead78-99e9-7d2a-9e47-042f1149a851" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-75ff-a0d2-1ea2e3cf7995" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019ead78-99e9-7d2a-9e47-042f1149a851" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails" xlink:type="simple" xlink:href="are-20260630.xsd#ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresConsolidatedVIEsbalancesheetinformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019ead78-99e9-77f8-b15e-729e819472b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfVariableInterestEntitiesTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019ead78-99e9-77f8-b15e-729e819472b6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis_019ead78-99e9-77bc-a143-d64c43c1fa78" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019ead78-99e9-77f8-b15e-729e819472b6" xlink:to="loc_srt_ConsolidatedEntitiesAxis_019ead78-99e9-77bc-a143-d64c43c1fa78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019ead78-99e9-77bc-a143-d64c43c1fa78_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019ead78-99e9-77bc-a143-d64c43c1fa78" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019ead78-99e9-77bc-a143-d64c43c1fa78_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain_019ead78-99e9-7fb6-8ec8-e83763933194" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidatedEntitiesAxis_019ead78-99e9-77bc-a143-d64c43c1fa78" xlink:to="loc_srt_ConsolidatedEntitiesDomain_019ead78-99e9-7fb6-8ec8-e83763933194" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019ead78-99e9-7073-8638-7dfa60efbcc2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidatedEntitiesDomain_019ead78-99e9-7fb6-8ec8-e83763933194" xlink:to="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryMember_019ead78-99e9-7073-8638-7dfa60efbcc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faa00-5a41-7216-b7a4-e1f0bcabb41f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019ead78-99e9-77f8-b15e-729e819472b6" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faa00-5a41-7216-b7a4-e1f0bcabb41f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faa00-5a41-7216-b7a4-e1f0bcabb41f_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faa00-5a41-7216-b7a4-e1f0bcabb41f" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faa00-5a41-7216-b7a4-e1f0bcabb41f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faa00-5a41-7b20-b48c-d17399749fb1" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019faa00-5a41-7216-b7a4-e1f0bcabb41f" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faa00-5a41-7b20-b48c-d17399749fb1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A99CoolidgeAvenueMember_019faa00-5a41-78d0-b75c-51dce6f4f3e0" xlink:href="are-20260630.xsd#are_A99CoolidgeAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019faa00-5a41-7b20-b48c-d17399749fb1" xlink:to="loc_are_A99CoolidgeAvenueMember_019faa00-5a41-78d0-b75c-51dce6f4f3e0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_019faa00-5a41-7d9a-930a-000ea4633e43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfVariableInterestEntitiesTable_019ead78-99e9-77f8-b15e-729e819472b6" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_019faa00-5a41-7d9a-930a-000ea4633e43" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019faa00-5a41-7d9a-930a-000ea4633e43_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019faa00-5a41-7d9a-930a-000ea4633e43" xlink:to="loc_us-gaap_EquityComponentDomain_019faa00-5a41-7d9a-930a-000ea4633e43_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_019faa00-5a41-7299-9820-ad7c08096d64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_019faa00-5a41-7d9a-930a-000ea4633e43" xlink:to="loc_us-gaap_EquityComponentDomain_019faa00-5a41-7299-9820-ad7c08096d64" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncontrollingInterestMember_019faa00-5a41-76aa-9bb8-3e4893183d19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncontrollingInterestMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_019faa00-5a41-7299-9820-ad7c08096d64" xlink:to="loc_us-gaap_NoncontrollingInterestMember_019faa00-5a41-76aa-9bb8-3e4893183d19" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7d1f-bee3-e338c556a1e9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-99e9-7d1f-bee3-e338c556a1e9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019ead78-99e9-77f9-82ef-691b360f7f97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019ead78-99e9-77f9-82ef-691b360f7f97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssets_019ead78-99e9-7d89-a34b-037082d970fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_OtherAssets_019ead78-99e9-7d89-a34b-037082d970fc" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019ead78-99e9-7b8f-bf12-4439454eaf56" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_Assets_019ead78-99e9-7b8f-bf12-4439454eaf56" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredDebt_019ead78-99e9-739c-bec7-6b7d6f1bc78a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_SecuredDebt_019ead78-99e9-739c-bec7-6b7d6f1bc78a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilities_019ead78-99e9-7237-aaf1-1c906bd7c60e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_OtherLiabilities_019ead78-99e9-7237-aaf1-1c906bd7c60e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_019ead78-99e9-72ac-b09e-651bea6eb1c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Liabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_Liabilities_019ead78-99e9-72ac-b09e-651bea6eb1c5" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_019ead78-99e9-710e-855b-307fa404f30c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_TemporaryEquityCarryingAmountIncludingPortionAttributableToNoncontrollingInterests_019ead78-99e9-710e-855b-307fa404f30c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_019ead78-99e9-77a5-a652-e5a6bf3a92c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_StockholdersEquity_019ead78-99e9-77a5-a652-e5a6bf3a92c4" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterest_019ead78-99e9-7e5e-a1ae-71523d141b74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_MinorityInterest_019ead78-99e9-7e5e-a1ae-71523d141b74" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ead78-99e9-70b6-bada-e56b8d9ca84d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_019ead78-99e9-70b6-bada-e56b8d9ca84d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MinorityInterestInJointVentures_019faa00-5a41-7b11-a0d8-c939c1c903cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_MinorityInterestInJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_MinorityInterestInJointVentures_019faa00-5a41-7b11-a0d8-c939c1c903cb" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemableNoncontrollingInterestEquityFairValue_019faa00-5a41-72dc-bfc7-7d38ad29b874" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RedeemableNoncontrollingInterestEquityFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_RedeemableNoncontrollingInterestEquityFairValue_019faa00-5a41-72dc-bfc7-7d38ad29b874" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RedeemableNoncontrollingInterestAccretionRate_019faa00-5a41-78cd-9652-6515f2e988fd" xlink:href="are-20260630.xsd#are_RedeemableNoncontrollingInterestAccretionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_are_RedeemableNoncontrollingInterestAccretionRate_019faa00-5a41-78cd-9652-6515f2e988fd" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchasesAndRedemptionsOfNoncontrollingInterests_019faa00-5a41-7246-8ee2-f6bae93e8301" xlink:href="are-20260630.xsd#are_PurchasesAndRedemptionsOfNoncontrollingInterests"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_are_PurchasesAndRedemptionsOfNoncontrollingInterests_019faa00-5a41-7246-8ee2-f6bae93e8301" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToMinorityShareholders_019faa00-5a41-7d10-980d-19b17170390a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToMinorityShareholders"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableInterestEntityLineItems_019ead78-99e9-7870-828e-d241b152f579" xlink:to="loc_us-gaap_PaymentsToMinorityShareholders_019faa00-5a41-7d10-980d-19b17170390a" xlink:type="arc" order="15"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails" xlink:type="simple" xlink:href="are-20260630.xsd#ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/ConsolidatedandunconsolidatedrealestatejointventuresUnconsolidatedrealestatejointventuresDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-718e-8c6c-23d6b5cb6fdc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-718e-8c6c-23d6b5cb6fdc" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-7b22-8207-97cbc9998c07" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-718e-8c6c-23d6b5cb6fdc" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-7b22-8207-97cbc9998c07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7b22-8207-97cbc9998c07_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-7b22-8207-97cbc9998c07" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7b22-8207-97cbc9998c07_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7ff2-8adc-2a9d8cf4d30e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_019ead78-99e9-7b22-8207-97cbc9998c07" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7ff2-8adc-2a9d8cf4d30e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1655And1725ThirdStreetMember_019ead78-99e9-7a88-b257-fd2eff253668" xlink:href="are-20260630.xsd#are_A1655And1725ThirdStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7ff2-8adc-2a9d8cf4d30e" xlink:to="loc_are_A1655And1725ThirdStreetMember_019ead78-99e9-7a88-b257-fd2eff253668" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A101WestDickmanStreetMember_019ead78-99e9-7ba6-8af3-81a29d9e67b9" xlink:href="are-20260630.xsd#are_A101WestDickmanStreetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7ff2-8adc-2a9d8cf4d30e" xlink:to="loc_are_A101WestDickmanStreetMember_019ead78-99e9-7ba6-8af3-81a29d9e67b9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherunconsolidatedrealestatejointventuresMember_019ead78-99e9-77e1-9dcc-d373e936c750" xlink:href="are-20260630.xsd#are_OtherunconsolidatedrealestatejointventuresMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_019ead78-99e9-7ff2-8adc-2a9d8cf4d30e" xlink:to="loc_are_OtherunconsolidatedrealestatejointventuresMember_019ead78-99e9-77e1-9dcc-d373e936c750" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_019ead78-99e9-7caa-905f-b11c1c5e4e8c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_019ead78-99e9-718e-8c6c-23d6b5cb6fdc" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_019ead78-99e9-7caa-905f-b11c1c5e4e8c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_019ead78-99e9-7caa-905f-b11c1c5e4e8c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_019ead78-99e9-7caa-905f-b11c1c5e4e8c" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_019ead78-99e9-7caa-905f-b11c1c5e4e8c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_019ead78-99e9-7175-9260-2f348108e720" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeAxis_019ead78-99e9-7caa-905f-b11c1c5e4e8c" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_019ead78-99e9-7175-9260-2f348108e720" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_019ead78-99e9-77e5-af40-19dcc27da3d6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeDomain_019ead78-99e9-7175-9260-2f348108e720" xlink:to="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_019ead78-99e9-77e5-af40-19dcc27da3d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019ead78-99e9-7de0-ba69-b51a2c83674f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:to="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_019ead78-99e9-7de0-ba69-b51a2c83674f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019ead78-99e9-7c98-83cd-72d8eea6647d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:to="loc_us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_019ead78-99e9-7c98-83cd-72d8eea6647d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019ead78-99e9-71dc-95ef-74d5a6542ae5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_019ead78-99e9-71dc-95ef-74d5a6542ae5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:href="are-20260630.xsd#are_UnconsolidatedRealEstateJointVentureDebtAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsLineItems_019ead78-99e9-7489-9c87-b1302c8aa9cb" xlink:to="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_019ead78-99e9-72c3-9293-8d796d207c1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_019ead78-99e9-72c3-9293-8d796d207c1b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019ead78-99e9-77e9-a655-4bfa172454f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019ead78-99e9-77e9-a655-4bfa172454f4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-99e9-7b1c-a3d4-f29bbe459e3c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-99e9-7b1c-a3d4-f29bbe459e3c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-99e9-7ed1-8b9c-53177b9d65bc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-99e9-7ed1-8b9c-53177b9d65bc" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBorrowingCapacity_019ead78-99e9-7b12-8473-64a40fa7d7f7" xlink:href="are-20260630.xsd#are_DebtInstrumentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_are_DebtInstrumentBorrowingCapacity_019ead78-99e9-7b12-8473-64a40fa7d7f7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019ead78-99e9-7695-8647-000ae082b1e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_us-gaap_LongTermDebt_019ead78-99e9-7695-8647-000ae082b1e3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBasisSpreadOnVariableRateFloor_019ead78-99e9-79e1-84dc-25381464efaf" xlink:href="are-20260630.xsd#are_DebtInstrumentBasisSpreadOnVariableRateFloor"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_UnconsolidatedRealEstateJointVentureDebtAbstract_019ead78-99e9-76c8-900c-ceeb3d1665f8" xlink:to="loc_are_DebtInstrumentBasisSpreadOnVariableRateFloor_019ead78-99e9-79e1-84dc-25381464efaf" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/LeasesLessorDetails" xlink:type="simple" xlink:href="are-20260630.xsd#LeasesLessorDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/LeasesLessorDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ead78-99e9-74e9-89e9-9c27a9a4229e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:to="loc_srt_ProductOrServiceAxis_019ead78-99e9-74e9-89e9-9c27a9a4229e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e9-74e9-89e9-9c27a9a4229e_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e9-74e9-89e9-9c27a9a4229e" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e9-74e9-89e9-9c27a9a4229e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-99e9-7750-9a7b-5e902742d730" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-99e9-74e9-89e9-9c27a9a4229e" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-99e9-7750-9a7b-5e902742d730" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsMember_019ead78-99e9-7622-af50-11f1c5df47f8" xlink:href="are-20260630.xsd#are_IncomefromrentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-99e9-7750-9a7b-5e902742d730" xlink:to="loc_are_IncomefromrentalsMember_019ead78-99e9-7622-af50-11f1c5df47f8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019ead78-99e9-7fb3-8aad-e62d12706e92" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:to="loc_srt_StatementGeographicalAxis_019ead78-99e9-7fb3-8aad-e62d12706e92" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7fb3-8aad-e62d12706e92_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7fb3-8aad-e62d12706e92" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7fb3-8aad-e62d12706e92_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7ead-a0ae-124722e04f08" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-99e9-7fb3-8aad-e62d12706e92" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7ead-a0ae-124722e04f08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_019ead78-99e9-7e84-a964-9c3efd48562b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-99e9-7ead-a0ae-124722e04f08" xlink:to="loc_srt_NorthAmericaMember_019ead78-99e9-7e84-a964-9c3efd48562b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7a48-9cda-b88287d4777f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7a48-9cda-b88287d4777f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7a48-9cda-b88287d4777f_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7a48-9cda-b88287d4777f" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7a48-9cda-b88287d4777f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-99e9-7a48-9cda-b88287d4777f" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember_019ead78-99e9-734f-82a3-128ce87e0f67" xlink:href="are-20260630.xsd#are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_LandparcelssubjecttoleaseagreementthatcontainsapurchaseoptionMember_019ead78-99e9-734f-82a3-128ce87e0f67" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1201And1208EastlakeAvenueEastMember_019ead78-99e9-732d-b48c-e2f6be73a4e5" xlink:href="are-20260630.xsd#are_A1201And1208EastlakeAvenueEastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_A1201And1208EastlakeAvenueEastMember_019ead78-99e9-732d-b48c-e2f6be73a4e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1208EastlakeAvenueEastMember_019ead78-99e9-7d7f-8a1e-5807a08600a4" xlink:href="are-20260630.xsd#are_A1208EastlakeAvenueEastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_A1208EastlakeAvenueEastMember_019ead78-99e9-7d7f-8a1e-5807a08600a4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1201EastlakeAvenueEastMember_019ead78-99e9-773f-93e3-5b4af837ad9e" xlink:href="are-20260630.xsd#are_A1201EastlakeAvenueEastMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_A1201EastlakeAvenueEastMember_019ead78-99e9-773f-93e3-5b4af837ad9e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherOperatingPropertiesMember_019ead78-99e9-718f-b22e-9f293889cf07" xlink:href="are-20260630.xsd#are_OtherOperatingPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_OtherOperatingPropertiesMember_019ead78-99e9-718f-b22e-9f293889cf07" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A30003018WesternAvenueMember_019ead78-99e9-7035-8ba1-cbdbfc81c9c7" xlink:href="are-20260630.xsd#are_A30003018WesternAvenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-99e9-7172-9c05-c47290693229" xlink:to="loc_are_A30003018WesternAvenueMember_019ead78-99e9-7035-8ba1-cbdbfc81c9c7" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-7a7a-a548-76e2767b5614" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-7a7a-a548-76e2767b5614" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7a7a-a548-76e2767b5614_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-7a7a-a548-76e2767b5614" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7a7a-a548-76e2767b5614_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7e78-8b6e-ce6cbbdc8358" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_019ead78-99e9-7a7a-a548-76e2767b5614" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7e78-8b6e-ce6cbbdc8358" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019ead78-99e9-7b8e-b1e7-0f2f4f1a46dc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_019ead78-99e9-7e78-8b6e-ce6cbbdc8358" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_019ead78-99e9-7b8e-b1e7-0f2f4f1a46dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermAxis_019ead78-99e9-7de9-b4aa-b1c97854ece2" xlink:href="are-20260630.xsd#are_PurchaseOptionTermAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LessorLeaseDescriptionTable_019ead78-99e9-77eb-ae34-18cf4258056d" xlink:to="loc_are_PurchaseOptionTermAxis_019ead78-99e9-7de9-b4aa-b1c97854ece2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermDomain_019ead78-99e9-7de9-b4aa-b1c97854ece2_default" xlink:href="are-20260630.xsd#are_PurchaseOptionTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PurchaseOptionTermAxis_019ead78-99e9-7de9-b4aa-b1c97854ece2" xlink:to="loc_are_PurchaseOptionTermDomain_019ead78-99e9-7de9-b4aa-b1c97854ece2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermDomain_019ead78-99e9-77c1-afd3-8fdb6fd25150" xlink:href="are-20260630.xsd#are_PurchaseOptionTermDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PurchaseOptionTermAxis_019ead78-99e9-7de9-b4aa-b1c97854ece2" xlink:to="loc_are_PurchaseOptionTermDomain_019ead78-99e9-77c1-afd3-8fdb6fd25150" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermOneMember_019ead78-99e9-7d39-887b-d20b9330d898" xlink:href="are-20260630.xsd#are_PurchaseOptionTermOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_019ead78-99e9-77c1-afd3-8fdb6fd25150" xlink:to="loc_are_PurchaseOptionTermOneMember_019ead78-99e9-7d39-887b-d20b9330d898" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermTwoMember_019ead78-99e9-77e1-91fd-44262c3c8ca7" xlink:href="are-20260630.xsd#are_PurchaseOptionTermTwoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_019ead78-99e9-77c1-afd3-8fdb6fd25150" xlink:to="loc_are_PurchaseOptionTermTwoMember_019ead78-99e9-77e1-91fd-44262c3c8ca7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PurchaseOptionTermThreeMember_019ead78-99e9-7087-bb0f-9ec70a877de0" xlink:href="are-20260630.xsd#are_PurchaseOptionTermThreeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PurchaseOptionTermDomain_019ead78-99e9-77c1-afd3-8fdb6fd25150" xlink:to="loc_are_PurchaseOptionTermThreeMember_019ead78-99e9-7087-bb0f-9ec70a877de0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-75cf-a221-c59d737f2e18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfRealEstateProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_us-gaap_NumberOfRealEstateProperties_019ead78-99e9-75cf-a221-c59d737f2e18" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_019ead78-9a9d-7db6-878f-5cfbd1e7321b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_019ead78-9a9d-7db6-878f-5cfbd1e7321b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeaseDescriptionAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertiesSubjectToLeaseAgreementThatContainsAPurchaseOption_019ead78-9a9d-7680-a755-083863e90d3e" xlink:href="are-20260630.xsd#are_OperatingPropertiesSubjectToLeaseAgreementThatContainsAPurchaseOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_OperatingPropertiesSubjectToLeaseAgreementThatContainsAPurchaseOption_019ead78-9a9d-7680-a755-083863e90d3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LandParcelSubjectToLeaseAgreementThatContainsAPurchaseOption_019ead78-9a9d-70d8-aeb7-056a8d76a157" xlink:href="are-20260630.xsd#are_LandParcelSubjectToLeaseAgreementThatContainsAPurchaseOption"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LandParcelSubjectToLeaseAgreementThatContainsAPurchaseOption_019ead78-9a9d-70d8-aeb7-056a8d76a157" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_019ead78-9a9d-7f8f-8bee-97f2ad6b768f" xlink:href="are-20260630.xsd#are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_019ead78-9a9d-7f8f-8bee-97f2ad6b768f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RentCommenceDate_019ead78-9a9d-7117-a109-649427d906b4" xlink:href="are-20260630.xsd#are_RentCommenceDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_RentCommenceDate_019ead78-9a9d-7117-a109-649427d906b4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseRemainingLeaseTerm_019ead78-9a9d-7b2a-98b3-4a1d0d04e70e" xlink:href="are-20260630.xsd#are_LessorOperatingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LessorOperatingLeaseRemainingLeaseTerm_019ead78-9a9d-7b2a-98b3-4a1d0d04e70e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPercentage_019ead78-9a9d-7d5b-ae06-43c771bcb38b" xlink:href="are-20260630.xsd#are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPercentage_019ead78-9a9d-7d5b-ae06-43c771bcb38b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPurchasePrice_019ead78-9a9d-7856-9767-feb14612474c" xlink:href="are-20260630.xsd#are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPurchasePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LessorOperatingLeaseLesseeOptionToPurchaseUnderlyingAssetPurchasePrice_019ead78-9a9d-7856-9767-feb14612474c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorOperatingLeaseWeightedAveragePurchaseOptionExerciseDate_019ead78-9a9d-7ec0-a6f8-d703f621969e" xlink:href="are-20260630.xsd#are_LessorOperatingLeaseWeightedAveragePurchaseOptionExerciseDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_are_LessorOperatingLeaseWeightedAveragePurchaseOptionExerciseDate_019ead78-9a9d-7ec0-a6f8-d703f621969e" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeaseDescriptionAbstract_019ead78-9a9d-76f3-9038-d3a70269a917" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_019ead78-9a9d-7be8-bf1e-30f6786f436f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedRemainderOfFiscalYear_019ead78-9a9d-7be8-bf1e-30f6786f436f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019ead78-9a9d-74ec-986b-1df36c9220d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedNextTwelveMonths_019ead78-9a9d-74ec-986b-1df36c9220d2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019ead78-9a9d-7cbe-8045-3455fa470782" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedTwoYears_019ead78-9a9d-7cbe-8045-3455fa470782" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019ead78-9a9d-7782-ab4c-12d2a530ab03" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThreeYears_019ead78-9a9d-7782-ab4c-12d2a530ab03" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_019ead78-9a9d-77e6-bacb-6f6e7a13526a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedFourYears_019ead78-9a9d-77e6-bacb-6f6e7a13526a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_019ead78-9a9d-709b-a8de-38484e9ab071" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceivedThereafter_019ead78-9a9d-709b-a8de-38484e9ab071" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019ead78-9a9d-78c2-8018-beb6efa6b74e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LessorOperatingLeasePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorOperatingLeasePaymentsFiscalYearMaturityAbstract_019ead78-9a9d-773e-8304-19f87c236758" xlink:to="loc_us-gaap_LessorOperatingLeasePaymentsToBeReceived_019ead78-9a9d-78c2-8018-beb6efa6b74e" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetInvestmentInLeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfDirectFinancingLeases_019ead78-9a9d-7562-8930-e2201a64b8e8" xlink:href="are-20260630.xsd#are_NumberOfDirectFinancingLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_NumberOfDirectFinancingLeases_019ead78-9a9d-7562-8930-e2201a64b8e8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLease_019ead78-9a9d-726a-85ab-411b5e414d30" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLease_019ead78-9a9d-726a-85ab-411b5e414d30" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseRemainingLeaseTerm_019ead78-9a9d-7247-bf77-68fe73353d7d" xlink:href="are-20260630.xsd#are_LessorDirectFinancingLeaseRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_LessorDirectFinancingLeaseRemainingLeaseTerm_019ead78-9a9d-7247-bf77-68fe73353d7d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod_019ead78-9a9d-75c1-a9e9-14d1afaf3c4d" xlink:href="are-20260630.xsd#are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetOptionExercisePeriod_019ead78-9a9d-75c1-a9e9-14d1afaf3c4d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_019ead78-9a9d-7189-97f1-b02702d73829" xlink:href="are-20260630.xsd#are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_LessorDirectFinancingLeaseLesseeOptionToPurchaseUnderlyingAssetPeriodAfterRentCommencement_019ead78-9a9d-7189-97f1-b02702d73829" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfSalesTypeLeases_019ead78-9a9d-7b82-82e6-2ab4413a9daf" xlink:href="are-20260630.xsd#are_NumberOfSalesTypeLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_NumberOfSalesTypeLeases_019ead78-9a9d-7b82-82e6-2ab4413a9daf" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeLeaseNetInvestmentInLease_019ead78-9a9d-70d0-8b1a-661284518641" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeLeaseNetInvestmentInLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_us-gaap_SalesTypeLeaseNetInvestmentInLease_019ead78-9a9d-70d0-8b1a-661284518641" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PotentialAssetDispositionConsideration_019ead78-9a9d-7029-b964-c5c66b1f0d02" xlink:href="are-20260630.xsd#are_PotentialAssetDispositionConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_are_PotentialAssetDispositionConsideration_019ead78-9a9d-7029-b964-c5c66b1f0d02" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss_019ead78-9a9d-77d9-9f29-b12fdc883e0b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeaseAllowanceForCreditLoss_019ead78-9a9d-77d9-9f29-b12fdc883e0b" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_019ead78-9a9d-7bc4-9267-68ccf1fc3c28" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_019ead78-9a9d-7bc4-9267-68ccf1fc3c28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DirectFinancingLeaseUnearnedIncome_019ead78-9a9d-767b-ab64-8e8b6e018acb" xlink:href="are-20260630.xsd#are_DirectFinancingLeaseUnearnedIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:to="loc_are_DirectFinancingLeaseUnearnedIncome_019ead78-9a9d-767b-ab64-8e8b6e018acb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss_019ead78-9a9d-7286-aae3-922082f96b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:to="loc_us-gaap_NetInvestmentInLeaseAllowanceForCreditLoss_019ead78-9a9d-7286-aae3-922082f96b2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentInLease_019ead78-9a9d-79eb-95d5-5e37f040678d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetInvestmentInLease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DirectFinancingLeaseNetInvestmentInLeasesAbstract_019ead78-9a9d-7dbc-be88-b64090a633e3" xlink:to="loc_us-gaap_NetInvestmentInLease_019ead78-9a9d-79eb-95d5-5e37f040678d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_NetInvestmentInLeasesAbstract_019ead78-9a9d-7c46-bd90-09af34cc6fec" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear_019ead78-9a9d-76b8-9322-fa3349f0f0b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedRemainderOfFiscalYear_019ead78-9a9d-76b8-9322-fa3349f0f0b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths_019ead78-9a9d-7888-b131-9ef75cd9c537" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedNextTwelveMonths_019ead78-9a9d-7888-b131-9ef75cd9c537" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears_019ead78-9a9d-7887-a00c-17d7c68a7c64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedTwoYears_019ead78-9a9d-7887-a00c-17d7c68a7c64" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears_019ead78-9a9d-7d1b-8c89-8a35e57f1e29" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThreeYears_019ead78-9a9d-7d1b-8c89-8a35e57f1e29" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears_019ead78-9a9d-74c2-b889-97db30d709a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedFourYears_019ead78-9a9d-74c2-b889-97db30d709a9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter_019ead78-9a9d-7e1e-9842-b8740ac50b82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivableFiscalYearMaturityAbstract_019ead78-9a9d-7db6-b87b-ee80823fbac1" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceivedThereafter_019ead78-9a9d-7e1e-9842-b8740ac50b82" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived_019ead78-9a9d-7948-a22c-04378371b9a6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesLeaseReceivablePaymentsToBeReceived"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:href="are-20260630.xsd#are_IncomefromrentalsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LessorLeaseDescriptionLineItems_019ead78-99e9-794b-840e-cfae846e1ec5" xlink:to="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLeaseIncome_019ead78-9a9d-719d-bc61-89fff9ed8b0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:to="loc_us-gaap_OperatingLeaseLeaseIncome_019ead78-9a9d-719d-bc61-89fff9ed8b0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_019ead78-9a9d-78a0-9463-11f1c9be87e0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:to="loc_us-gaap_SalesTypeAndDirectFinancingLeasesInterestIncome_019ead78-9a9d-78a0-9463-11f1c9be87e0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseIncome_019ead78-9a9d-7e56-b67d-9c6f0dad7add" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:to="loc_us-gaap_LeaseIncome_019ead78-9a9d-7e56-b67d-9c6f0dad7add" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_019ead78-9a9d-7b8f-92e7-07a8ef6f40d7" xlink:href="are-20260630.xsd#are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:to="loc_are_RevenueSubjectToTheASUOnRecognitionOfRevenueArisingFromContractsWithCustomers_019ead78-9a9d-7b8f-92e7-07a8ef6f40d7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-7452-8d61-68cc76790962" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_IncomefromrentalsAbstract_019ead78-9a9d-7983-97e2-f3c4344081a7" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-7452-8d61-68cc76790962" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/LeasesLesseeDetails" xlink:type="simple" xlink:href="are-20260630.xsd#LeasesLesseeDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/LeasesLesseeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_019ead78-9a9d-71c8-ae4b-4f782e95b890" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_019ead78-9a9d-71c8-ae4b-4f782e95b890" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-9a9d-777a-8b7e-56fa68f88d05" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019ead78-9a9d-71c8-ae4b-4f782e95b890" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-9a9d-777a-8b7e-56fa68f88d05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-777a-8b7e-56fa68f88d05_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-9a9d-777a-8b7e-56fa68f88d05" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-777a-8b7e-56fa68f88d05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-7abc-8baa-8bb130c09269" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_019ead78-9a9d-777a-8b7e-56fa68f88d05" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-7abc-8baa-8bb130c09269" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundandOperatingLeasesMember_019ead78-9a9d-7820-84fa-99c0dd8e2ca3" xlink:href="are-20260630.xsd#are_GroundandOperatingLeasesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-7abc-8baa-8bb130c09269" xlink:to="loc_are_GroundandOperatingLeasesMember_019ead78-9a9d-7820-84fa-99c0dd8e2ca3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertyWithGroundLeaseMember_019ead78-9a9d-786d-a8c1-e2d6d1261cec" xlink:href="are-20260630.xsd#are_OperatingPropertyWithGroundLeaseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_019ead78-9a9d-7abc-8baa-8bb130c09269" xlink:to="loc_are_OperatingPropertyWithGroundLeaseMember_019ead78-9a9d-786d-a8c1-e2d6d1261cec" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ead78-9a9d-7292-a452-3c8bfa8da973" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019ead78-9a9d-71c8-ae4b-4f782e95b890" xlink:to="loc_srt_RangeAxis_019ead78-9a9d-7292-a452-3c8bfa8da973" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-9a9d-7292-a452-3c8bfa8da973_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ead78-9a9d-7292-a452-3c8bfa8da973" xlink:to="loc_srt_RangeMember_019ead78-9a9d-7292-a452-3c8bfa8da973_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-9a9d-7e55-955f-564a281a28cd" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ead78-9a9d-7292-a452-3c8bfa8da973" xlink:to="loc_srt_RangeMember_019ead78-9a9d-7e55-955f-564a281a28cd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019ead78-9a9d-7892-b13e-e13135a9cd40" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ead78-9a9d-7e55-955f-564a281a28cd" xlink:to="loc_srt_MinimumMember_019ead78-9a9d-7892-b13e-e13135a9cd40" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ead78-9a9d-7a5a-9673-ad1242bf56f0" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ead78-9a9d-7e55-955f-564a281a28cd" xlink:to="loc_srt_MaximumMember_019ead78-9a9d-7a5a-9673-ad1242bf56f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-9a9d-723e-bc57-7cfe63634a6b" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_019ead78-9a9d-71c8-ae4b-4f782e95b890" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-9a9d-723e-bc57-7cfe63634a6b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-9a9d-723e-bc57-7cfe63634a6b_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-9a9d-723e-bc57-7cfe63634a6b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-9a9d-723e-bc57-7cfe63634a6b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-9a9d-7a4a-bf2e-b96eb849d4da" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019ead78-9a9d-723e-bc57-7cfe63634a6b" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-9a9d-7a4a-bf2e-b96eb849d4da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AlexandriaTechnologySquareMember_019ead78-9a9d-761b-880c-13ed518f890a" xlink:href="are-20260630.xsd#are_AlexandriaTechnologySquareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019ead78-9a9d-7a4a-bf2e-b96eb849d4da" xlink:to="loc_are_AlexandriaTechnologySquareMember_019ead78-9a9d-761b-880c-13ed518f890a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_019ead78-9a9d-72b0-bd62-b8f07676d147" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeaseLiability_019ead78-9a9d-72b0-bd62-b8f07676d147" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_019ead78-9a9d-7b1e-af0d-10a1f3b20bdd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_019ead78-9a9d-7b1e-af0d-10a1f3b20bdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_019ead78-9a9d-7c36-9b1e-4f1cd1e552b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_019ead78-9a9d-7c36-9b1e-4f1cd1e552b0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_019ead78-9a9d-70ed-8c70-c63aa600273f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_019ead78-9a9d-70ed-8c70-c63aa600273f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfPropertiesSubjectToGroundLeases_019ead78-9a9d-7256-91dc-7c77ac1ebef2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfPropertiesSubjectToGroundLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_NumberOfPropertiesSubjectToGroundLeases_019ead78-9a9d-7256-91dc-7c77ac1ebef2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PercentageOfPropertiesSubjectToGroundLeases_019ead78-9a9d-7069-8dbe-9cf53227bd41" xlink:href="are-20260630.xsd#are_PercentageOfPropertiesSubjectToGroundLeases"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_are_PercentageOfPropertiesSubjectToGroundLeases_019ead78-9a9d-7069-8dbe-9cf53227bd41" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundLeaseRelatedToOperatingPropertyNetBookValue_019ead78-9a9d-7519-8370-5dc1f2d6335b" xlink:href="are-20260630.xsd#are_GroundLeaseRelatedToOperatingPropertyNetBookValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_are_GroundLeaseRelatedToOperatingPropertyNetBookValue_019ead78-9a9d-7519-8370-5dc1f2d6335b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GroundLeaseObligationRemainingLeaseTerm_019ead78-9a9d-7881-b23a-45bb5dcd4a97" xlink:href="are-20260630.xsd#are_GroundLeaseObligationRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_are_GroundLeaseObligationRemainingLeaseTerm_019ead78-9a9d-7881-b23a-45bb5dcd4a97" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_019ead78-9a9d-7282-b2a9-3b6b6dc3dad8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeasePayments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeasePayments_019ead78-9a9d-7282-b2a9-3b6b6dc3dad8" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingLeaseObligationRemainingLeaseTerm_019ead78-9a9d-7ed1-93ba-1c0afef22633" xlink:href="are-20260630.xsd#are_OperatingLeaseObligationRemainingLeaseTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_are_OperatingLeaseObligationRemainingLeaseTerm_019ead78-9a9d-7ed1-93ba-1c0afef22633" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_019ead78-9a9d-7678-945e-23ad70942a7d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_019ead78-9a9d-7678-945e-23ad70942a7d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_019ead78-9a9d-7d0b-aa96-b4732458545b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_019ead78-9a9d-7d0b-aa96-b4732458545b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_019ead78-9a9d-7f78-8354-4f46a9f69e0a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_019ead78-9a9d-7f78-8354-4f46a9f69e0a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_019ead78-9a9d-7806-b43e-05fdefdcd090" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_019ead78-9a9d-7806-b43e-05fdefdcd090" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_019ead78-9a9d-71d5-906d-6d006ef60286" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_019ead78-9a9d-71d5-906d-6d006ef60286" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_019ead78-9a9d-778b-be07-604d18d9046f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_019ead78-9a9d-778b-be07-604d18d9046f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_019ead78-9a9d-7ed6-8f20-77031b8ce94b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_019ead78-9a9d-7ed6-8f20-77031b8ce94b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_019ead78-9a9d-7b73-92cf-37698ec510de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_019ead78-9a9d-7279-a463-4bbb0d95eaac" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_019ead78-9a9d-7b73-92cf-37698ec510de" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_019ead78-9a9d-7635-9b4e-30dae60484e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostAbstract_019ead78-9a9d-7d84-b603-ff633ae43553" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseCostAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_019ead78-9a9d-7828-83f1-2f09b9764547" xlink:to="loc_us-gaap_LeaseCostAbstract_019ead78-9a9d-7d84-b603-ff633ae43553" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_019ead78-9a9d-7c2f-b13f-f7d3cbff8d0f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingLeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_019ead78-9a9d-7d84-b603-ff633ae43553" xlink:to="loc_us-gaap_OperatingLeaseCost_019ead78-9a9d-7c2f-b13f-f7d3cbff8d0f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CapitalizedLeaseCosts_019ead78-9a9d-7874-85be-0a35a3d87ff8" xlink:href="are-20260630.xsd#are_CapitalizedLeaseCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_019ead78-9a9d-7d84-b603-ff633ae43553" xlink:to="loc_are_CapitalizedLeaseCosts_019ead78-9a9d-7874-85be-0a35a3d87ff8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCost_019ead78-9a9d-7c06-9ecf-4cb253571239" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LeaseCostAbstract_019ead78-9a9d-7d84-b603-ff633ae43553" xlink:to="loc_us-gaap_LeaseCost_019ead78-9a9d-7c06-9ecf-4cb253571239" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/CashcashequivalentsandrestrictedcashDetails" xlink:type="simple" xlink:href="are-20260630.xsd#CashcashequivalentsandrestrictedcashDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/CashcashequivalentsandrestrictedcashDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsLineItems_019ead78-9a9d-75ae-8020-7c1d0d2cdefb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019ead78-9a9d-7e29-a1af-7e6f462999b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfCashAndCashEquivalentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019ead78-9a9d-75ae-8020-7c1d0d2cdefb" xlink:to="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019ead78-9a9d-7e29-a1af-7e6f462999b9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019ead78-9a9d-702e-b211-d7dcc5cb3b49" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfCashAndCashEquivalentsTable_019ead78-9a9d-7e29-a1af-7e6f462999b9" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019ead78-9a9d-702e-b211-d7dcc5cb3b49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-702e-b211-d7dcc5cb3b49_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019ead78-9a9d-702e-b211-d7dcc5cb3b49" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-702e-b211-d7dcc5cb3b49_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-7426-9cc0-38b7315dfa07" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis_019ead78-9a9d-702e-b211-d7dcc5cb3b49" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-7426-9cc0-38b7315dfa07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DevelopmentEscrowsMember_019ead78-9a9d-7793-85e4-a3de66e4bcbe" xlink:href="are-20260630.xsd#are_DevelopmentEscrowsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-7426-9cc0-38b7315dfa07" xlink:to="loc_are_DevelopmentEscrowsMember_019ead78-9a9d-7793-85e4-a3de66e4bcbe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SecurityDepositsMember_019ead78-9a9d-7be3-a60f-5577c5a12e1d" xlink:href="are-20260630.xsd#are_SecurityDepositsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-7426-9cc0-38b7315dfa07" xlink:to="loc_are_SecurityDepositsMember_019ead78-9a9d-7be3-a60f-5577c5a12e1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OtherrestrictedcashMember_019ead78-9a9d-711e-b88a-c4de52080c21" xlink:href="are-20260630.xsd#are_OtherrestrictedcashMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_019ead78-9a9d-7426-9cc0-38b7315dfa07" xlink:to="loc_are_OtherrestrictedcashMember_019ead78-9a9d-711e-b88a-c4de52080c21" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019ead78-9a9d-72a8-ad5e-d667c54939e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019ead78-9a9d-75ae-8020-7c1d0d2cdefb" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_019ead78-9a9d-72a8-ad5e-d667c54939e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019ead78-9a9d-7793-8af3-b861f25b63dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019ead78-9a9d-75ae-8020-7c1d0d2cdefb" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsAtCarryingValue_019ead78-9a9d-7793-8af3-b861f25b63dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019ead78-9a9d-70b9-8e3e-4cc0312f3398" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CashAndCashEquivalentsLineItems_019ead78-9a9d-75ae-8020-7c1d0d2cdefb" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_019ead78-9a9d-70b9-8e3e-4cc0312f3398" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsNarrativesDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsNarrativesDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsNarrativesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7422-8f70-6f7b57f745d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7422-8f70-6f7b57f745d5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7259-a35f-d5a202aa1b0b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7422-8f70-6f7b57f745d5" xlink:to="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7259-a35f-d5a202aa1b0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7259-a35f-d5a202aa1b0b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7259-a35f-d5a202aa1b0b" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7259-a35f-d5a202aa1b0b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-78c9-8d43-60630588f66f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7259-a35f-d5a202aa1b0b" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-78c9-8d43-60630588f66f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7d06-9f1f-ac1a6b7159c3" xlink:href="are-20260630.xsd#are_LimitedpartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-78c9-8d43-60630588f66f" xlink:to="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7d06-9f1f-ac1a6b7159c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-774c-b03f-71f00f435a0e" xlink:href="are-20260630.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-78c9-8d43-60630588f66f" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-774c-b03f-71f00f435a0e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-79fb-adc4-f2c32198d8f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7422-8f70-6f7b57f745d5" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-79fb-adc4-f2c32198d8f8" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-79fb-adc4-f2c32198d8f8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-79fb-adc4-f2c32198d8f8" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-79fb-adc4-f2c32198d8f8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7a54-8183-c3552d8ceb31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-79fb-adc4-f2c32198d8f8" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7a54-8183-c3552d8ceb31" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-70e0-ba46-e4b9bcdd7010" xlink:href="are-20260630.xsd#are_EntitieswithobservablepricechangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7a54-8183-c3552d8ceb31" xlink:to="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-70e0-ba46-e4b9bcdd7010" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_019ead78-9a9d-7e10-adbd-b48a52c1634d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_EquityMethodInvestments_019ead78-9a9d-7e10-adbd-b48a52c1634d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments_019ead78-9a9d-71be-bf07-3cd6ff97e8d8" xlink:href="are-20260630.xsd#are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_are_FairValueInvestmentsPrivatelyHeldEntitiesThatCalculateNAVUnfundedCommitments_019ead78-9a9d-71be-bf07-3cd6ff97e8d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedPartnershipMaximumExpirationTerms_019ead78-9a9d-7e00-b4df-97180a73e9e9" xlink:href="are-20260630.xsd#are_LimitedPartnershipMaximumExpirationTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_are_LimitedPartnershipMaximumExpirationTerms_019ead78-9a9d-7e00-b4df-97180a73e9e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1_019ead78-9a9d-7b2d-a0a8-8f16ece644c8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareLiquidatingInvestmentRemainingPeriod1_019ead78-9a9d-7b2d-a0a8-8f16ece644c8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedPartnershipLiquidationExpectedInitialTermInYears_019ead78-9a9d-7dde-a162-b17f509731a9" xlink:href="are-20260630.xsd#are_LimitedPartnershipLiquidationExpectedInitialTermInYears"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_are_LimitedPartnershipLiquidationExpectedInitialTermInYears_019ead78-9a9d-7dde-a162-b17f509731a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_NumberOfEquityMethodInvestments_019ead78-9a9d-774b-ae02-7ae6a3537365" xlink:href="are-20260630.xsd#are_NumberOfEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_are_NumberOfEquityMethodInvestments_019ead78-9a9d-774b-ae02-7ae6a3537365" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount_019ead78-9a9d-7237-96b1-f1b20c04ca0f" xlink:href="are-20260630.xsd#are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentCumulativeAmount_019ead78-9a9d-7237-96b1-f1b20c04ca0f" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount_019ead78-9a9d-7875-a360-e3cb40ea9a1f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentCumulativeAmount_019ead78-9a9d-7875-a360-e3cb40ea9a1f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount_019ead78-9a9d-7ada-bb75-7ec34cc50eff" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentCumulativeAmount_019ead78-9a9d-7ada-bb75-7ec34cc50eff" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_019ead78-9a9d-758d-8459-bbb9a1073def" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-71db-8260-9b0749a43648" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossCumulativeAmount_019ead78-9a9d-758d-8459-bbb9a1073def" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsSummaryofInvestmentsDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsSummaryofInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsSummaryofInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7c70-8f7b-d216d5261b0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7c70-8f7b-d216d5261b0c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7df3-ac8d-b3c9b241a631" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7c70-8f7b-d216d5261b0c" xlink:to="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7df3-ac8d-b3c9b241a631" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7df3-ac8d-b3c9b241a631_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7df3-ac8d-b3c9b241a631" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7df3-ac8d-b3c9b241a631_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7a1d-8f6a-727a32b7ca54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7df3-ac8d-b3c9b241a631" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7a1d-8f6a-727a32b7ca54" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinpubliclytradedcompaniesMember_019ead78-9a9d-7449-81b3-9ddff57dbf63" xlink:href="are-20260630.xsd#are_InvestmentsinpubliclytradedcompaniesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7a1d-8f6a-727a32b7ca54" xlink:to="loc_are_InvestmentsinpubliclytradedcompaniesMember_019ead78-9a9d-7449-81b3-9ddff57dbf63" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7b24-ba53-c181e758dafc" xlink:href="are-20260630.xsd#are_LimitedpartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7a1d-8f6a-727a32b7ca54" xlink:to="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7b24-ba53-c181e758dafc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-76fe-99ce-54e33417f698" xlink:href="are-20260630.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7a1d-8f6a-727a32b7ca54" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-76fe-99ce-54e33417f698" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7b05-8234-9ccb5414f44d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7c70-8f7b-d216d5261b0c" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7b05-8234-9ccb5414f44d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7b05-8234-9ccb5414f44d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7b05-8234-9ccb5414f44d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7b05-8234-9ccb5414f44d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7f09-90f5-9cd9f73fc9d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7b05-8234-9ccb5414f44d" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7f09-90f5-9cd9f73fc9d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-7748-b290-0e1027ec326a" xlink:href="are-20260630.xsd#are_EntitieswithobservablepricechangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7f09-90f5-9cd9f73fc9d2" xlink:to="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-7748-b290-0e1027ec326a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithoutobservablepricechangesMember_019ead78-9a9d-7307-b4a2-760b2d95e4a5" xlink:href="are-20260630.xsd#are_EntitieswithoutobservablepricechangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7f09-90f5-9cd9f73fc9d2" xlink:to="loc_are_EntitieswithoutobservablepricechangesMember_019ead78-9a9d-7307-b4a2-760b2d95e4a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCost_019ead78-9a9d-71ec-b016-67f6f54cb542" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCost_019ead78-9a9d-71ec-b016-67f6f54cb542" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CumulativeUnrealizedGainsOnInvestments_019ead78-9a9d-7d68-ae9f-bcf79a660ea7" xlink:href="are-20260630.xsd#are_CumulativeUnrealizedGainsOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_are_CumulativeUnrealizedGainsOnInvestments_019ead78-9a9d-7d68-ae9f-bcf79a660ea7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CumulativeUnrealizedLossesOnInvestments_019ead78-9a9d-7860-8eaf-9776b41e56a5" xlink:href="are-20260630.xsd#are_CumulativeUnrealizedLossesOnInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_are_CumulativeUnrealizedLossesOnInvestments_019ead78-9a9d-7860-8eaf-9776b41e56a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_019ead78-9a9d-73d6-be73-b8b32f6fb017" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_019ead78-9a9d-73d6-be73-b8b32f6fb017" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019ead78-9a9d-7a80-9b5e-b3b0e04d5aac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019ead78-9a9d-7a80-9b5e-b3b0e04d5aac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_019ead78-9a9d-7f18-ae05-92b037cabb70" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_EquityMethodInvestments_019ead78-9a9d-7f18-ae05-92b037cabb70" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_019ead78-9a9d-7744-9d4c-b75ad9597213" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7ae7-bc59-1f6f03630880" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_019ead78-9a9d-7744-9d4c-b75ad9597213" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsInvestmentIncomeDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsInvestmentIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsInvestmentIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7413-9779-0dd2686b0150" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7413-9779-0dd2686b0150" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis_019ead78-9a9d-788b-9031-efc30e52bfe5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-7413-9779-0dd2686b0150" xlink:to="loc_us-gaap_FairValueByAssetClassAxis_019ead78-9a9d-788b-9031-efc30e52bfe5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019ead78-9a9d-788b-9031-efc30e52bfe5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019ead78-9a9d-788b-9031-efc30e52bfe5" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019ead78-9a9d-788b-9031-efc30e52bfe5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019ead78-9a9d-752f-bc48-7ae62245c816" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByAssetClassAxis_019ead78-9a9d-788b-9031-efc30e52bfe5" xlink:to="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019ead78-9a9d-752f-bc48-7ae62245c816" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_019ead78-9a9d-75e1-93b5-c9759f6534c3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationByAssetClassDomain_019ead78-9a9d-752f-bc48-7ae62245c816" xlink:to="loc_us-gaap_EquityMethodInvestmentsMember_019ead78-9a9d-75e1-93b5-c9759f6534c3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_019ead78-9a9d-79c0-a49c-bbc901f288aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiRealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_EquitySecuritiesFvNiRealizedGainLoss_019ead78-9a9d-79c0-a49c-bbc901f288aa" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019ead78-9a9d-7a40-b615-e4ec2254126a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019ead78-9a9d-7a40-b615-e4ec2254126a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-9a9d-78cc-ae20-d7018492bbc6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-9a9d-78cc-ae20-d7018492bbc6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiRealizedGain_019ead78-9a9d-71be-934f-0b0ac2de591e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiRealizedGain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_EquitySecuritiesFvNiRealizedGain_019ead78-9a9d-71be-934f-0b0ac2de591e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount_019ead78-9a9d-7cfa-9cb4-50745cf7a7c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueImpairmentLossAnnualAmount_019ead78-9a9d-7cfa-9cb4-50745cf7a7c7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-9a9d-7bad-a3b7-4c235d5f635b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7db4-a968-fee8e6548a81" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-9a9d-7bad-a3b7-4c235d5f635b" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/InvestmentsScheduleofUnrealizedGainsLossesonInvestmentsDetails" xlink:type="simple" xlink:href="are-20260630.xsd#InvestmentsScheduleofUnrealizedGainsLossesonInvestmentsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/InvestmentsScheduleofUnrealizedGainsLossesonInvestmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-746c-838f-ce2b63234253" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:to="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-746c-838f-ce2b63234253" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7a6a-82bb-c5d05eed82d5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-746c-838f-ce2b63234253" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7a6a-82bb-c5d05eed82d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7a6a-82bb-c5d05eed82d5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7a6a-82bb-c5d05eed82d5" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7a6a-82bb-c5d05eed82d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7d5a-a8c2-73d44d669565" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-7a6a-82bb-c5d05eed82d5" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7d5a-a8c2-73d44d669565" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitiesWithObservablePriceChangeMember_019ead78-9a9d-70dd-a196-7f38975f448f" xlink:href="are-20260630.xsd#are_EntitiesWithObservablePriceChangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7d5a-a8c2-73d44d669565" xlink:to="loc_are_EntitiesWithObservablePriceChangeMember_019ead78-9a9d-70dd-a196-7f38975f448f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-7c8e-976e-96ca83166109" xlink:href="are-20260630.xsd#are_EntitieswithobservablepricechangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-7d5a-a8c2-73d44d669565" xlink:to="loc_are_EntitieswithobservablepricechangeMember_019ead78-9a9d-7c8e-976e-96ca83166109" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7d41-a47f-b3570c933648" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_019ead78-9a9d-746c-838f-ce2b63234253" xlink:to="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7d41-a47f-b3570c933648" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7d41-a47f-b3570c933648_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7d41-a47f-b3570c933648" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-7d41-a47f-b3570c933648_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-70b2-9773-afc51f93e968" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-7d41-a47f-b3570c933648" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-70b2-9773-afc51f93e968" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-7965-87d5-a2f90d091a09" xlink:href="are-20260630.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-70b2-9773-afc51f93e968" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-7965-87d5-a2f90d091a09" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TotalInvestmentsHeldMember_019ead78-9a9d-7fc4-acbf-9cff541db0f4" xlink:href="are-20260630.xsd#are_TotalInvestmentsHeldMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-70b2-9773-afc51f93e968" xlink:to="loc_are_TotalInvestmentsHeldMember_019ead78-9a9d-7fc4-acbf-9cff541db0f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount_019ead78-9a9d-7f06-b64a-cad6b5cf3c74" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueUpwardPriceAdjustmentAnnualAmount_019ead78-9a9d-7f06-b64a-cad6b5cf3c74" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount_019ead78-9a9d-7db9-8f58-c3fbfa7f6378" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueDownwardPriceAdjustmentAnnualAmount_019ead78-9a9d-7db9-8f58-c3fbfa7f6378" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentAnnualAmount_019ead78-9a9d-77e8-a7c9-034fd3e2ab3a" xlink:href="are-20260630.xsd#are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentAnnualAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:to="loc_are_EquitySecuritiesWithoutReadilyDeterminableFairValuePriceAdjustmentAnnualAmount_019ead78-9a9d-77e8-a7c9-034fd3e2ab3a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019ead78-9a9d-763b-992d-2dd150a912ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryLineItems_019ead78-9a9d-7e55-93f3-1e0ff2d763a3" xlink:to="loc_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_019ead78-9a9d-763b-992d-2dd150a912ca" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/OtherassetsDetail" xlink:type="simple" xlink:href="are-20260630.xsd#OtherassetsDetail"/>
  <link:definitionLink xlink:role="http://www.are.com/role/OtherassetsDetail" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ead78-9a9d-7173-a100-312911eb9911" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ead78-9a9d-7173-a100-312911eb9911" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ead78-9a9d-72a6-80ed-bf0612cef56e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ead78-9a9d-7173-a100-312911eb9911" xlink:to="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ead78-9a9d-72a6-80ed-bf0612cef56e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ead78-9a9d-72a6-80ed-bf0612cef56e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ead78-9a9d-72a6-80ed-bf0612cef56e" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ead78-9a9d-72a6-80ed-bf0612cef56e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableTypeDomain_019ead78-9a9d-73d7-8362-e0a8537aca6c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_019ead78-9a9d-72a6-80ed-bf0612cef56e" xlink:to="loc_us-gaap_ReceivableTypeDomain_019ead78-9a9d-73d7-8362-e0a8537aca6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableMember_019ead78-9a9d-7c00-a1f7-745f0d580191" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ReceivableTypeDomain_019ead78-9a9d-73d7-8362-e0a8537aca6c" xlink:to="loc_us-gaap_NotesReceivableMember_019ead78-9a9d-7c00-a1f7-745f0d580191" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_019ead78-9a9d-709d-a3bb-3be53315604c" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ead78-9a9d-7173-a100-312911eb9911" xlink:to="loc_srt_StatementGeographicalAxis_019ead78-9a9d-709d-a3bb-3be53315604c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-709d-a3bb-3be53315604c_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-9a9d-709d-a3bb-3be53315604c" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-709d-a3bb-3be53315604c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-7691-8ffe-8142cd6fdc2f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_019ead78-9a9d-709d-a3bb-3be53315604c" xlink:to="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-7691-8ffe-8142cd6fdc2f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SanDiegoMember_019ead78-9a9d-70a2-829e-d0ec8fb708b1" xlink:href="are-20260630.xsd#are_SanDiegoMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-7691-8ffe-8142cd6fdc2f" xlink:to="loc_are_SanDiegoMember_019ead78-9a9d-70a2-829e-d0ec8fb708b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_GreaterBostonMember_019ead78-9a9d-74a8-8496-40507016bbc2" xlink:href="are-20260630.xsd#are_GreaterBostonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_019ead78-9a9d-7691-8ffe-8142cd6fdc2f" xlink:to="loc_are_GreaterBostonMember_019ead78-9a9d-74a8-8496-40507016bbc2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019f0018-de34-7e7c-9361-f1c5def0aa2c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_019ead78-9a9d-7173-a100-312911eb9911" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019f0018-de34-7e7c-9361-f1c5def0aa2c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019f0018-de34-7e7c-9361-f1c5def0aa2c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019f0018-de34-7e7c-9361-f1c5def0aa2c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019f0018-de34-7e7c-9361-f1c5def0aa2c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019f0018-de34-7e10-a771-5759728dd314" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019f0018-de34-7e7c-9361-f1c5def0aa2c" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019f0018-de34-7e10-a771-5759728dd314" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019f0019-5540-7b12-a8ce-20bc91539913" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019f0018-de34-7e10-a771-5759728dd314" xlink:to="loc_us-gaap_SubsequentEventMember_019f0019-5540-7b12-a8ce-20bc91539913" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableWithImputedInterestEffectiveYieldInterestRate_019ead78-9a9d-715a-ac06-829b8b8b2a0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableWithImputedInterestEffectiveYieldInterestRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_ReceivableWithImputedInterestEffectiveYieldInterestRate_019ead78-9a9d-715a-ac06-829b8b8b2a0c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReceivableWithImputedInterestDueDates_019ead78-9a9d-7457-a487-696c2e28bb7a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReceivableWithImputedInterestDueDates"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_ReceivableWithImputedInterestDueDates_019ead78-9a9d-7457-a487-696c2e28bb7a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesAndLoansReceivableGrossNoncurrent_019ead78-9a9d-7cb8-8fff-b8515f186cd9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesAndLoansReceivableGrossNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_NotesAndLoansReceivableGrossNoncurrent_019ead78-9a9d-7cb8-8fff-b8515f186cd9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019ead78-9a9d-726b-8317-7ee3acd03da3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FinancingReceivableAllowanceForCreditLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_FinancingReceivableAllowanceForCreditLosses_019ead78-9a9d-726b-8317-7ee3acd03da3" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NotesReceivableNet_019ead78-9a9d-7863-af75-b4365d99028c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_NotesReceivableNet_019ead78-9a9d-7863-af75-b4365d99028c" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProvisionForDoubtfulAccounts_019ead78-9a9d-77f9-bf43-6274070ba708" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProvisionForDoubtfulAccounts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_019ead78-9a9d-7191-8e79-6161e13870cc" xlink:to="loc_us-gaap_ProvisionForDoubtfulAccounts_019ead78-9a9d-77f9-bf43-6274070ba708" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails" xlink:type="simple" xlink:href="are-20260630.xsd#FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/FairvaluemeasurementsAssetsandLiabilitiesonRecurringandNonrecurringBasisDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-73b0-808e-2ab2d8387c4f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsForNewAccountingPronouncementsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-73b0-808e-2ab2d8387c4f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-73b0-808e-2ab2d8387c4f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-73b0-808e-2ab2d8387c4f" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-73b0-808e-2ab2d8387c4f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-74cc-b30a-0409b3e136dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TypeOfAdoptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForNewAccountingPronouncementsAxis_019ead78-9a9d-73b0-808e-2ab2d8387c4f" xlink:to="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-74cc-b30a-0409b3e136dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_EntitieswithoutobservablepricechangesMember_019ead78-9a9d-7e45-bfbf-9a08551bc8cf" xlink:href="are-20260630.xsd#are_EntitieswithoutobservablepricechangesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfAdoptionMember_019ead78-9a9d-74cc-b30a-0409b3e136dd" xlink:to="loc_are_EntitieswithoutobservablepricechangesMember_019ead78-9a9d-7e45-bfbf-9a08551bc8cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-73c0-95a1-bdef77cab42a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-73c0-95a1-bdef77cab42a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-73c0-95a1-bdef77cab42a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-73c0-95a1-bdef77cab42a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-73c0-95a1-bdef77cab42a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-75d5-b89e-c06e5b7f31ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_019ead78-9a9d-73c0-95a1-bdef77cab42a" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-75d5-b89e-c06e5b7f31ba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsInPubliclyTradedCompaniesMember_019ead78-9a9d-7eca-97e1-3164fb69d79d" xlink:href="are-20260630.xsd#are_InvestmentsInPubliclyTradedCompaniesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-75d5-b89e-c06e5b7f31ba" xlink:to="loc_are_InvestmentsInPubliclyTradedCompaniesMember_019ead78-9a9d-7eca-97e1-3164fb69d79d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7c49-84ef-4d12723cd8d8" xlink:href="are-20260630.xsd#are_LimitedpartnershipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-75d5-b89e-c06e5b7f31ba" xlink:to="loc_are_LimitedpartnershipsMember_019ead78-9a9d-7c49-84ef-4d12723cd8d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-73f1-aa76-35d5f5370a6b" xlink:href="are-20260630.xsd#are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_019ead78-9a9d-75d5-b89e-c06e5b7f31ba" xlink:to="loc_are_InvestmentsinprivatelyheldentitiesthatdonotreportNAVMember_019ead78-9a9d-73f1-aa76-35d5f5370a6b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_019ead78-9a9d-76f8-8ae0-829a58f92be4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementBasisAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_019ead78-9a9d-76f8-8ae0-829a58f92be4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-76f8-8ae0-829a58f92be4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019ead78-9a9d-76f8-8ae0-829a58f92be4" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-76f8-8ae0-829a58f92be4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ead78-9a9d-79f5-9f5c-f5c2af1fd383" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_019ead78-9a9d-76f8-8ae0-829a58f92be4" xlink:to="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ead78-9a9d-79f5-9f5c-f5c2af1fd383" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-7c2f-a8b2-c109216c836e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain_019ead78-9a9d-79f5-9f5c-f5c2af1fd383" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-7c2f-a8b2-c109216c836e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019ead78-9a9d-7ef1-b03e-6ec07229eee4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-7c2f-a8b2-c109216c836e" xlink:to="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_019ead78-9a9d-7ef1-b03e-6ec07229eee4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019ead78-9a9d-7714-ab23-e127b27fd875" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_019ead78-9a9d-7c2f-a8b2-c109216c836e" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_019ead78-9a9d-7714-ab23-e127b27fd875" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ead78-9a9d-7f71-b911-b0f6e01a5e18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_019ead78-9a9d-7e1e-bc7d-2f66a33c39f2" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ead78-9a9d-7f71-b911-b0f6e01a5e18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019ead78-9a9d-7c67-957f-8c4130cfa1f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_019ead78-9a9d-7f71-b911-b0f6e01a5e18" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_019ead78-9a9d-7c67-957f-8c4130cfa1f7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ead78-9a9d-725c-933b-ff2e6cc1b966" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ead78-9a9d-725c-933b-ff2e6cc1b966" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-725c-933b-ff2e6cc1b966_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ead78-9a9d-725c-933b-ff2e6cc1b966" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-725c-933b-ff2e6cc1b966_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-7085-b654-e28636105f19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_019ead78-9a9d-725c-933b-ff2e6cc1b966" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-7085-b654-e28636105f19" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_019ead78-9a9d-7282-a807-83b584ab6671" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-7085-b654-e28636105f19" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_019ead78-9a9d-7282-a807-83b584ab6671" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_019ead78-9a9d-7a3a-a07a-cd91f964426f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-7085-b654-e28636105f19" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_019ead78-9a9d-7a3a-a07a-cd91f964426f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_019ead78-9a9d-7f60-a3f3-1511fac1af3f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_019ead78-9a9d-7085-b654-e28636105f19" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_019ead78-9a9d-7f60-a3f3-1511fac1af3f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bc7-a480-5afebb43e0cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bc7-a480-5afebb43e0cb" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7bc7-a480-5afebb43e0cb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bc7-a480-5afebb43e0cb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7bc7-a480-5afebb43e0cb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7757-8235-73026c8183d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bc7-a480-5afebb43e0cb" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7757-8235-73026c8183d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A22BillionUnsecuredSeniorLineOfCreditMember_019ead78-9a9d-7925-842e-f6db852189ea" xlink:href="are-20260630.xsd#are_A22BillionUnsecuredSeniorLineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7757-8235-73026c8183d8" xlink:to="loc_are_A22BillionUnsecuredSeniorLineOfCreditMember_019ead78-9a9d-7925-842e-f6db852189ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7eac-9257-55611a3697d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7eac-9257-55611a3697d3" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7eac-9257-55611a3697d3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7eac-9257-55611a3697d3" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7eac-9257-55611a3697d3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-721e-b575-5ab82bcb0df6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7eac-9257-55611a3697d3" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-721e-b575-5ab82bcb0df6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-7e1a-b83d-e224defc44e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-721e-b575-5ab82bcb0df6" xlink:to="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-7e1a-b83d-e224defc44e5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7524-9979-bc3e79fba638" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_019ead78-9a9d-7405-868f-e08138ebc96e" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7524-9979-bc3e79fba638" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7524-9979-bc3e79fba638_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7524-9979-bc3e79fba638" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7524-9979-bc3e79fba638_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7376-be33-8f089699f9b8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7524-9979-bc3e79fba638" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7376-be33-8f089699f9b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7274-95cd-5314d5da3912" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CurrencySwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7376-be33-8f089699f9b8" xlink:to="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7274-95cd-5314d5da3912" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_TransfersInFairValueHierarchy_019ead78-9a9d-7ef1-8803-293e966b8378" xlink:href="are-20260630.xsd#are_TransfersInFairValueHierarchy"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_are_TransfersInFairValueHierarchy_019ead78-9a9d-7ef1-8803-293e966b8378" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNi_019ead78-9a9d-763e-89f7-b1722cadf15b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNi"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_EquitySecuritiesFvNi_019ead78-9a9d-763e-89f7-b1722cadf15b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue_019ead78-9a9d-7747-a0c1-13681ef67128" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue_019ead78-9a9d-7747-a0c1-13681ef67128" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue_019ead78-9a9d-7e6e-b7eb-c5d64d7abac1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue_019ead78-9a9d-7e6e-b7eb-c5d64d7abac1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue_019ead78-9a9d-79c1-acfa-db787cffd723" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_EquitySecuritiesFvNiAndWithoutReadilyDeterminableFairValue_019ead78-9a9d-79c1-acfa-db787cffd723" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_019ead78-9a9d-715f-927d-08a8af9679be" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateHeldforsale_019ead78-9a9d-7295-81c3-17472d81efaf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateHeldforsale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_RealEstateHeldforsale_019ead78-9a9d-7295-81c3-17472d81efaf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_019ead78-9a9d-7bef-9193-8249d28f7394" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_AssetsHeldForSaleLongLivedFairValueDisclosure_019ead78-9a9d-7bef-9193-8249d28f7394" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019ead78-9a9d-75ce-b8a9-b51d6dcdb40b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_EquitySecuritiesWithoutReadilyDeterminableFairValueAmount_019ead78-9a9d-75ce-b8a9-b51d6dcdb40b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorLongTermNotes_019ead78-9a9d-7c88-a1e1-a87e035a50dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorLongTermNotes"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_SeniorLongTermNotes_019ead78-9a9d-7c88-a1e1-a87e035a50dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_SeniorNotesFairValueDisclosure_019ead78-9a9d-7d79-af29-c8239e86e088" xlink:href="are-20260630.xsd#are_SeniorNotesFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_are_SeniorNotesFairValueDisclosure_019ead78-9a9d-7d79-af29-c8239e86e088" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCredit_019ead78-9a9d-7484-a27c-9f176b877774" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_LineOfCredit_019ead78-9a9d-7484-a27c-9f176b877774" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LinesOfCreditFairValueDisclosure_019ead78-9a9d-779d-a1ce-ee419b82a6bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LinesOfCreditFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_LinesOfCreditFairValueDisclosure_019ead78-9a9d-779d-a1ce-ee419b82a6bd" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaper_019ead78-9a9d-742e-884c-d7ecc4d8eff1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_us-gaap_CommercialPaper_019ead78-9a9d-742e-884c-d7ecc4d8eff1" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommercialPaperFairValueDisclosure_019ead78-9a9d-73db-a9e5-22a6d6871692" xlink:href="are-20260630.xsd#are_CommercialPaperFairValueDisclosure"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringValueMeasurementAbstract_019ead78-9a9d-775f-be14-e13b96f9eb54" xlink:to="loc_are_CommercialPaperFairValueDisclosure_019ead78-9a9d-73db-a9e5-22a6d6871692" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/DetailofsecuredandunsecureddebtDetails" xlink:type="simple" xlink:href="are-20260630.xsd#DetailofsecuredandunsecureddebtDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/DetailofsecuredandunsecureddebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-72a1-8d63-c2c13bca036c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-72a1-8d63-c2c13bca036c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7b63-96f5-b47b699c8da9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-72a1-8d63-c2c13bca036c" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7b63-96f5-b47b699c8da9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7b63-96f5-b47b699c8da9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7b63-96f5-b47b699c8da9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7b63-96f5-b47b699c8da9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-74d5-9501-e92e6cfbeb58" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7b63-96f5-b47b699c8da9" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-74d5-9501-e92e6cfbeb58" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-7eb0-8292-2e46babfff32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-74d5-9501-e92e6cfbeb58" xlink:to="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-7eb0-8292-2e46babfff32" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-79d0-a7bb-631359b4e3ce" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-72a1-8d63-c2c13bca036c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-79d0-a7bb-631359b4e3ce" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-79d0-a7bb-631359b4e3ce_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-79d0-a7bb-631359b4e3ce" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-79d0-a7bb-631359b4e3ce_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7323-9b8c-8f8d294f2a16" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-79d0-a7bb-631359b4e3ce" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7323-9b8c-8f8d294f2a16" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnsecuredDebtMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7323-9b8c-8f8d294f2a16" xlink:to="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-72ae-b17e-4880566dd9e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-72ae-b17e-4880566dd9e4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.95UnsecuredSeniorNotesPayableMember_019ead78-9a9d-79cd-bca5-80df186977a6" xlink:href="are-20260630.xsd#are_A3.95UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A3.95UnsecuredSeniorNotesPayableMember_019ead78-9a9d-79cd-bca5-80df186977a6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.95UnsecuredSeniorNotesPayableDuein2028Member_019ead78-9a9d-7694-a014-428b065aa559" xlink:href="are-20260630.xsd#are_A3.95UnsecuredSeniorNotesPayableDuein2028Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A3.95UnsecuredSeniorNotesPayableDuein2028Member_019ead78-9a9d-7694-a014-428b065aa559" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_UnsecuredSeniorNotesDueinJuly2029Member_019ead78-9a9d-79ea-8871-dbe37ca0bf6a" xlink:href="are-20260630.xsd#are_UnsecuredSeniorNotesDueinJuly2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_UnsecuredSeniorNotesDueinJuly2029Member_019ead78-9a9d-79ea-8871-dbe37ca0bf6a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A2.75UnsecuredSeniorNotesPayableDue2029Member_019ead78-9a9d-754b-a2a3-d906f6eecb0d" xlink:href="are-20260630.xsd#are_A2.75UnsecuredSeniorNotesPayableDue2029Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A2.75UnsecuredSeniorNotesPayableDue2029Member_019ead78-9a9d-754b-a2a3-d906f6eecb0d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.70UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7810-b71b-fdbd6c7b8e85" xlink:href="are-20260630.xsd#are_A4.70UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A4.70UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7810-b71b-fdbd6c7b8e85" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.90UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7301-979a-37d61316357c" xlink:href="are-20260630.xsd#are_A4.90UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A4.90UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7301-979a-37d61316357c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.375UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7da4-a74f-97892a0b3fa2" xlink:href="are-20260630.xsd#are_A3.375UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A3.375UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7da4-a74f-97892a0b3fa2" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A200UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7bae-a28b-acc23c9f299d" xlink:href="are-20260630.xsd#are_A200UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A200UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7bae-a28b-acc23c9f299d" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A1875UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76e4-8da5-a6854836c125" xlink:href="are-20260630.xsd#are_A1875UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A1875UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76e4-8da5-a6854836c125" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A295UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7508-a63c-741c6d29c16d" xlink:href="are-20260630.xsd#are_A295UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A295UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7508-a63c-741c6d29c16d" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A475UnsecuredSeniorNotesPayableMember_019ead78-9a9d-74d8-aa1d-e87cde1a6e68" xlink:href="are-20260630.xsd#are_A475UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A475UnsecuredSeniorNotesPayableMember_019ead78-9a9d-74d8-aa1d-e87cde1a6e68" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5.50UnsecuredSeniorNotesPayableMember_019ead78-9a9d-704f-a6d2-deea2ddfb8a0" xlink:href="are-20260630.xsd#are_A5.50UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A5.50UnsecuredSeniorNotesPayableMember_019ead78-9a9d-704f-a6d2-deea2ddfb8a0" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5.25UnsecuredSeniorNotesPayableDue2036Member_019ead78-9a9d-7428-b15c-28698ecf3920" xlink:href="are-20260630.xsd#are_A5.25UnsecuredSeniorNotesPayableDue2036Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A5.25UnsecuredSeniorNotesPayableDue2036Member_019ead78-9a9d-7428-b15c-28698ecf3920" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5.25UnsecuredSeniorNotesPayableMember_019ead78-9a9d-74ea-9a7e-4559b2e3f630" xlink:href="are-20260630.xsd#are_A5.25UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A5.25UnsecuredSeniorNotesPayableMember_019ead78-9a9d-74ea-9a7e-4559b2e3f630" xlink:type="arc" order="15"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.85UnsecuredSeniorNotePayableMember_019ead78-9a9d-7b8a-9e7d-ba9ff2ca7133" xlink:href="are-20260630.xsd#are_A4.85UnsecuredSeniorNotePayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A4.85UnsecuredSeniorNotePayableMember_019ead78-9a9d-7b8a-9e7d-ba9ff2ca7133" xlink:type="arc" order="16"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.00UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7023-b7e8-0c6e09cfb3a5" xlink:href="are-20260630.xsd#are_A4.00UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A4.00UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7023-b7e8-0c6e09cfb3a5" xlink:type="arc" order="17"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A300UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7368-a23c-fbd3a8fc58f6" xlink:href="are-20260630.xsd#are_A300UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A300UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7368-a23c-fbd3a8fc58f6" xlink:type="arc" order="18"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A355UnsecuredSeniorNotesPayableMember_019ead78-9a9d-78f8-bf46-2e18362a55c0" xlink:href="are-20260630.xsd#are_A355UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A355UnsecuredSeniorNotesPayableMember_019ead78-9a9d-78f8-bf46-2e18362a55c0" xlink:type="arc" order="19"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A515UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7a96-af1c-5d2bb18a5d22" xlink:href="are-20260630.xsd#are_A515UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A515UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7a96-af1c-5d2bb18a5d22" xlink:type="arc" order="20"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5.625UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76b3-891b-0683969e3d1b" xlink:href="are-20260630.xsd#are_A5.625UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_UnsecuredDebtMember_019ead78-9a9d-79ff-950c-fc7ab283fcbf" xlink:to="loc_are_A5.625UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76b3-891b-0683969e3d1b" xlink:type="arc" order="21"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-73c5-8847-e8f376a67672" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-72a1-8d63-c2c13bca036c" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-73c5-8847-e8f376a67672" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-73c5-8847-e8f376a67672_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-73c5-8847-e8f376a67672" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-73c5-8847-e8f376a67672_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-71e5-8987-fef65614691d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-73c5-8847-e8f376a67672" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-71e5-8987-fef65614691d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019ead78-9a9d-7ed7-aec6-d75eaf54347f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-71e5-8987-fef65614691d" xlink:to="loc_us-gaap_SubsequentEventMember_019ead78-9a9d-7ed7-aec6-d75eaf54347f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-9a9d-7d9f-8c18-46775c4e8720" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-9a9d-7d9f-8c18-46775c4e8720" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-9a9d-799f-8fa5-e303d457a1bf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-9a9d-799f-8fa5-e303d457a1bf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentMaturityDate_019ead78-9a9d-7fef-8705-e5649480ca53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentMaturityDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_DebtInstrumentMaturityDate_019ead78-9a9d-7fef-8705-e5649480ca53" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ead78-9a9d-72cf-9754-14766594e823" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ead78-9a9d-72cf-9754-14766594e823" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtByMaturityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7afe-ba51-1aeb2ca175e2" xlink:to="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019ead78-9a9d-73b6-8a9d-d6b313a33380" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_019ead78-9a9d-73b6-8a9d-d6b313a33380" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019ead78-9a9d-70c7-b3b1-01439ef01af6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_019ead78-9a9d-70c7-b3b1-01439ef01af6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019ead78-9a9d-73b5-b1f8-68266ba82ee7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_019ead78-9a9d-73b5-b1f8-68266ba82ee7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019ead78-9a9d-701b-8d62-ed0846f9f2e8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_019ead78-9a9d-701b-8d62-ed0846f9f2e8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019ead78-9a9d-738b-9981-561eccc8bfdf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive_019ead78-9a9d-738b-9981-561eccc8bfdf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_019ead78-9a9d-782c-a712-6217319ca508" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_019ead78-9a9d-782c-a712-6217319ca508" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-75c5-8482-fc8491fcdc98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-75c5-8482-fc8491fcdc98" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019ead78-9a9d-752f-80ec-297015b61854" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNet_019ead78-9a9d-752f-80ec-297015b61854" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019ead78-9a9d-7ae5-b6b0-7dfed899e9fc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongTermDebtByMaturityAbstract_019ead78-9a9d-744f-b7f5-9c4149f4ae64" xlink:to="loc_us-gaap_LongTermDebt_019ead78-9a9d-7ae5-b6b0-7dfed899e9fc" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SummaryofsecuredandunsecureddebtDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SummaryofsecuredandunsecureddebtDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SummaryofsecuredandunsecureddebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-74d8-897e-945040debf02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-74d8-897e-945040debf02" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bdf-8d09-03f73cd2445a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-74d8-897e-945040debf02" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bdf-8d09-03f73cd2445a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7bdf-8d09-03f73cd2445a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bdf-8d09-03f73cd2445a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7bdf-8d09-03f73cd2445a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7e01-9cc9-9ac5406182f7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7bdf-8d09-03f73cd2445a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7e01-9cc9-9ac5406182f7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_019ead78-9a9d-7625-bcdf-b1166d2f24ec" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7e01-9cc9-9ac5406182f7" xlink:to="loc_us-gaap_SeniorNotesMember_019ead78-9a9d-7625-bcdf-b1166d2f24ec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-7da0-9f9f-e7b4de55da27" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7e01-9cc9-9ac5406182f7" xlink:to="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-7da0-9f9f-e7b4de55da27" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7d75-8834-86d7507be268" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-74d8-897e-945040debf02" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7d75-8834-86d7507be268" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7d75-8834-86d7507be268_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7d75-8834-86d7507be268" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7d75-8834-86d7507be268_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7bb0-996e-4e1c5b7bc8c9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-7d75-8834-86d7507be268" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7bb0-996e-4e1c5b7bc8c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-793d-ba1e-0160006769e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-7bb0-996e-4e1c5b7bc8c9" xlink:to="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-793d-ba1e-0160006769e2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LongtermDebtPercentageBearingFixedInterestAmountNet_019ead78-9a9d-7683-a5b5-245510f3bbc2" xlink:href="are-20260630.xsd#are_LongtermDebtPercentageBearingFixedInterestAmountNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_LongtermDebtPercentageBearingFixedInterestAmountNet_019ead78-9a9d-7683-a5b5-245510f3bbc2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LongtermDebtPercentageBearingVariableInterestAmountNet_019ead78-9a9d-7f09-9163-4b72d5739dc7" xlink:href="are-20260630.xsd#are_LongtermDebtPercentageBearingVariableInterestAmountNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_LongtermDebtPercentageBearingVariableInterestAmountNet_019ead78-9a9d-7f09-9163-4b72d5739dc7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019ead78-9a9d-7f0d-a83e-daa0cb8724cb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_us-gaap_LongTermDebt_019ead78-9a9d-7f0d-a83e-daa0cb8724cb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentPercentageOfOutstandingBalance_019ead78-9a9d-7c24-b88a-62a5e714f1c8" xlink:href="are-20260630.xsd#are_DebtInstrumentPercentageOfOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_DebtInstrumentPercentageOfOutstandingBalance_019ead78-9a9d-7c24-b88a-62a5e714f1c8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-9a9d-702b-ad0c-a22aee0f7434" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_019ead78-9a9d-702b-ad0c-a22aee0f7434" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentWeightedAverageRemainingPeriod_019ead78-9a9d-72b0-8f41-671e50cbf4f9" xlink:href="are-20260630.xsd#are_DebtInstrumentWeightedAverageRemainingPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_DebtInstrumentWeightedAverageRemainingPeriod_019ead78-9a9d-72b0-8f41-671e50cbf4f9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance_019ead78-9a9d-7dd4-aab1-cb69e003a6a3" xlink:href="are-20260630.xsd#are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_FixedInterestRateDebtAsPercentageOfTotalOutstandingBalance_019ead78-9a9d-7dd4-aab1-cb69e003a6a3" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance_019ead78-9a9d-7b00-8241-ba465e899cc8" xlink:href="are-20260630.xsd#are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_VariableInterestRateDebtAsPercentageOfTotalOutstandingBalance_019ead78-9a9d-7b00-8241-ba465e899cc8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-7dc3-85ae-e84b2ccb9aea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-7dc3-85ae-e84b2ccb9aea" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageYieldToMaturityCommercialPaper_019ead78-9a9d-718b-bc2e-aac08144af5c" xlink:href="are-20260630.xsd#are_WeightedAverageYieldToMaturityCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_WeightedAverageYieldToMaturityCommercialPaper_019ead78-9a9d-718b-bc2e-aac08144af5c" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_019ead78-9a9d-786b-8fc0-328d96f4ddcd" xlink:href="are-20260630.xsd#are_WeightedAverageRemainingMaturityTermCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7b5e-b760-bd4b5af3b6df" xlink:to="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_019ead78-9a9d-786b-8fc0-328d96f4ddcd" xlink:type="arc" order="10"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/UnsecuredseniornotespayableLOCandcommercialpaperDetails" xlink:type="simple" xlink:href="are-20260630.xsd#UnsecuredseniornotespayableLOCandcommercialpaperDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/UnsecuredseniornotespayableLOCandcommercialpaperDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7a3d-a233-29b858c22338" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7a3d-a233-29b858c22338" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7a3d-a233-29b858c22338_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7a3d-a233-29b858c22338" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-7a3d-a233-29b858c22338_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_019ead78-9a9d-7a3d-a233-29b858c22338" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.00UnsecuredSeniorNotes3.00UnsecuredSeniorNotesAnd3.55UnsecuredSeniorNotesMember_019ead78-9a9d-7912-ab81-c1a2293825e1" xlink:href="are-20260630.xsd#are_A4.00UnsecuredSeniorNotes3.00UnsecuredSeniorNotesAnd3.55UnsecuredSeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A4.00UnsecuredSeniorNotes3.00UnsecuredSeniorNotesAnd3.55UnsecuredSeniorNotesMember_019ead78-9a9d-7912-ab81-c1a2293825e1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.00UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7e31-b70b-6659478e6649" xlink:href="are-20260630.xsd#are_A4.00UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A4.00UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7e31-b70b-6659478e6649" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A300UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7e7f-93c0-0f673fe9495e" xlink:href="are-20260630.xsd#are_A300UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A300UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7e7f-93c0-0f673fe9495e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A355UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76d3-b309-1c4e28c5237a" xlink:href="are-20260630.xsd#are_A355UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A355UnsecuredSeniorNotesPayableMember_019ead78-9a9d-76d3-b309-1c4e28c5237a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A5.25UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7674-be5c-3ab4f0979fd3" xlink:href="are-20260630.xsd#are_A5.25UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A5.25UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7674-be5c-3ab4f0979fd3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A4.30UnsecuredSeniorNotesPayableMember_019ead78-9a9d-711c-8688-f5b6187278fd" xlink:href="are-20260630.xsd#are_A4.30UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A4.30UnsecuredSeniorNotesPayableMember_019ead78-9a9d-711c-8688-f5b6187278fd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3.80UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7935-bc6b-25e03de53185" xlink:href="are-20260630.xsd#are_A3.80UnsecuredSeniorNotesPayableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_are_A3.80UnsecuredSeniorNotesPayableMember_019ead78-9a9d-7935-bc6b-25e03de53185" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-7553-a0e3-9f25579f74ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_019ead78-9a9d-788d-8fb9-f64bae738f84" xlink:to="loc_us-gaap_LineOfCreditMember_019ead78-9a9d-7553-a0e3-9f25579f74ed" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-717b-8da9-8db995974af2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:to="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-717b-8da9-8db995974af2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-717b-8da9-8db995974af2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-717b-8da9-8db995974af2" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-717b-8da9-8db995974af2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-79a1-ab94-6c715561913f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis_019ead78-9a9d-717b-8da9-8db995974af2" xlink:to="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-79a1-ab94-6c715561913f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-77db-ba2c-80207ee165fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommercialPaperMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain_019ead78-9a9d-79a1-ab94-6c715561913f" xlink:to="loc_us-gaap_CommercialPaperMember_019ead78-9a9d-77db-ba2c-80207ee165fe" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_019ead78-9a9d-7597-b9a2-abe50c3190af" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:to="loc_srt_RangeAxis_019ead78-9a9d-7597-b9a2-abe50c3190af" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-9a9d-7597-b9a2-abe50c3190af_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_019ead78-9a9d-7597-b9a2-abe50c3190af" xlink:to="loc_srt_RangeMember_019ead78-9a9d-7597-b9a2-abe50c3190af_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_019ead78-9a9d-753d-ae2b-d5e7c006fc48" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_019ead78-9a9d-7597-b9a2-abe50c3190af" xlink:to="loc_srt_RangeMember_019ead78-9a9d-753d-ae2b-d5e7c006fc48" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_019ead78-9a9d-7e3d-97f6-4a5249c4003e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ead78-9a9d-753d-ae2b-d5e7c006fc48" xlink:to="loc_srt_MinimumMember_019ead78-9a9d-7e3d-97f6-4a5249c4003e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_019ead78-9a9d-72e7-96c1-34fa61ce617f" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_019ead78-9a9d-753d-ae2b-d5e7c006fc48" xlink:to="loc_srt_MaximumMember_019ead78-9a9d-72e7-96c1-34fa61ce617f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019fb017-ce19-7dcd-9dc9-7b82ae098df9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_019ead78-9a9d-798d-b11b-e9d4eafd51f9" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019fb017-ce19-7dcd-9dc9-7b82ae098df9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fb017-ce19-7dcd-9dc9-7b82ae098df9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fb017-ce19-7dcd-9dc9-7b82ae098df9" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fb017-ce19-7dcd-9dc9-7b82ae098df9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019fb017-ce19-71bf-8b45-6b724bc4b871" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019fb017-ce19-7dcd-9dc9-7b82ae098df9" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019fb017-ce19-71bf-8b45-6b724bc4b871" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019fb017-ea8c-754b-aa3b-e29cd818b066" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019fb017-ce19-71bf-8b45-6b724bc4b871" xlink:to="loc_us-gaap_SubsequentEventMember_019fb017-ea8c-754b-aa3b-e29cd818b066" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-7131-804d-f515925a3719" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_019ead78-9a9d-7131-804d-f515925a3719" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-9a9d-718e-b77b-574f438c17bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_019ead78-9a9d-718e-b77b-574f438c17bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfCommercialPaper_019ead78-9a9d-77bb-ba55-5273fdbad4c4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromIssuanceOfCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfCommercialPaper_019ead78-9a9d-77bb-ba55-5273fdbad4c4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RepaymentsOfUnsecuredDebt_019ead78-9a9d-72cc-b5bf-905aa44fa621" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RepaymentsOfUnsecuredDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_RepaymentsOfUnsecuredDebt_019ead78-9a9d-72cc-b5bf-905aa44fa621" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-9a9d-7cb8-80fa-9ba2ef0dbcc3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-9a9d-7cb8-80fa-9ba2ef0dbcc3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ead78-9a9d-7180-8c59-4e3cd3b6b21f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_019ead78-9a9d-7180-8c59-4e3cd3b6b21f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019ead78-9a9d-7cb7-baa8-a896d6e8919c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_019ead78-9a9d-7cb7-baa8-a896d6e8919c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019ead78-9a9d-72c1-a2b1-d391b9562c26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_019ead78-9a9d-72c1-a2b1-d391b9562c26" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentInterestRateAdjustmentAmountMaximum_019ead78-9a9d-745b-a6e5-7fe3eac2d952" xlink:href="are-20260630.xsd#are_DebtInstrumentInterestRateAdjustmentAmountMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_are_DebtInstrumentInterestRateAdjustmentAmountMaximum_019ead78-9a9d-745b-a6e5-7fe3eac2d952" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum_019ead78-9a9d-71bc-a96f-fe48c3d4064a" xlink:href="are-20260630.xsd#are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_are_DebtInstrumentFacilityFeeRateAdjustmentAmountMaximum_019ead78-9a9d-71bc-a96f-fe48c3d4064a" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease_019ead78-9a9d-7749-857e-23c52a576da8" xlink:href="are-20260630.xsd#are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_are_DebtInstrumentBasisSpreadOnVariableRatePeriodIncreaseDecrease_019ead78-9a9d-7749-857e-23c52a576da8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_019ead78-9a9d-74e9-98b0-5da9c09bdbe0" xlink:href="are-20260630.xsd#are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_are_LineOfCreditFacilityCommitmentFeePercentagePeriodIncreaseDecrease_019ead78-9a9d-74e9-98b0-5da9c09bdbe0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_019ead78-9a9d-7cb0-98ec-fa6109b8139d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LineOfCreditFacilityAbstract_019ead78-9a9d-7ebc-bb13-4308b7b6f8c5" xlink:to="loc_us-gaap_LongTermDebt_019ead78-9a9d-7cb0-98ec-fa6109b8139d" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_019ead78-9a9d-7a1a-957c-4ccac9b34f6e" xlink:to="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommercialPaperMaximumIssuance_019ead78-9a9d-7f24-8f51-56e0f7477887" xlink:href="are-20260630.xsd#are_CommercialPaperMaximumIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:to="loc_are_CommercialPaperMaximumIssuance_019ead78-9a9d-7f24-8f51-56e0f7477887" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTerm_019ead78-9a9d-78ac-91b7-bff5615dfe25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:to="loc_us-gaap_DebtInstrumentTerm_019ead78-9a9d-78ac-91b7-bff5615dfe25" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageYieldToMaturityCommercialPaper_019ead78-9a9d-7421-aaa9-1250098b8744" xlink:href="are-20260630.xsd#are_WeightedAverageYieldToMaturityCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:to="loc_are_WeightedAverageYieldToMaturityCommercialPaper_019ead78-9a9d-7421-aaa9-1250098b8744" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_019ead78-9a9d-7b50-970c-ccc3e32c7915" xlink:href="are-20260630.xsd#are_WeightedAverageRemainingMaturityTermCommercialPaper"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermCommercialPaperCurrentAndNoncurrentAbstract_019ead78-9a9d-72fc-91ac-32694c04a3de" xlink:to="loc_are_WeightedAverageRemainingMaturityTermCommercialPaper_019ead78-9a9d-7b50-970c-ccc3e32c7915" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/HedgeAgreementsDetails" xlink:type="simple" xlink:href="are-20260630.xsd#HedgeAgreementsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/HedgeAgreementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019ead78-9a9d-7398-b117-af70d06f0c31" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019ead78-9a9d-7398-b117-af70d06f0c31" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7dd2-a39f-fb5f937edc02" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019ead78-9a9d-7398-b117-af70d06f0c31" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7dd2-a39f-fb5f937edc02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7dd2-a39f-fb5f937edc02_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7dd2-a39f-fb5f937edc02" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7dd2-a39f-fb5f937edc02_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7641-a6bc-90c6cff0ea7f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-7dd2-a39f-fb5f937edc02" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7641-a6bc-90c6cff0ea7f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7747-a9db-6bf749b1fb2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CurrencySwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7641-a6bc-90c6cff0ea7f" xlink:to="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7747-a9db-6bf749b1fb2e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_019ead78-9a9d-728b-a03c-c5e299b00dd1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019ead78-9a9d-7398-b117-af70d06f0c31" xlink:to="loc_us-gaap_HedgingDesignationAxis_019ead78-9a9d-728b-a03c-c5e299b00dd1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019ead78-9a9d-728b-a03c-c5e299b00dd1_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_019ead78-9a9d-728b-a03c-c5e299b00dd1" xlink:to="loc_us-gaap_HedgingDesignationDomain_019ead78-9a9d-728b-a03c-c5e299b00dd1_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_019ead78-9a9d-7890-8861-09a00c7c0f51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_019ead78-9a9d-728b-a03c-c5e299b00dd1" xlink:to="loc_us-gaap_HedgingDesignationDomain_019ead78-9a9d-7890-8861-09a00c7c0f51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019ead78-9a9d-7388-8ed6-9a4bc00b794b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_019ead78-9a9d-7890-8861-09a00c7c0f51" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_019ead78-9a9d-7388-8ed6-9a4bc00b794b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7e71-bbfd-27977444be41" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresTable_019ead78-9a9d-7398-b117-af70d06f0c31" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7e71-bbfd-27977444be41" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-7e71-bbfd-27977444be41_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7e71-bbfd-27977444be41" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-7e71-bbfd-27977444be41_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71a9-8c04-7ef37d9b60aa" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7e71-bbfd-27977444be41" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71a9-8c04-7ef37d9b60aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_019ead78-9a9d-7348-a432-e71f49b7c9be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71a9-8c04-7ef37d9b60aa" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_019ead78-9a9d-7348-a432-e71f49b7c9be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue_019ead78-9a9d-72f5-afd7-9b343e8a0005" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeInstrumentsInHedgesAssetsAtFairValue_019ead78-9a9d-72f5-afd7-9b343e8a0005" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue_019ead78-9a9d-70c3-88c0-c21b49c23af4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeInstrumentsInHedgesLiabilitiesAtFairValue_019ead78-9a9d-70c3-88c0-c21b49c23af4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_019ead78-9a9d-7b54-a3fe-fa780145904a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_019ead78-9a9d-7b54-a3fe-fa780145904a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_019ead78-9a9d-7f61-8561-5d6bdf998f01" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeLiabilityStatementOfFinancialPositionExtensibleEnumeration_019ead78-9a9d-7f61-8561-5d6bdf998f01" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_019ead78-9a9d-7ec4-b226-f5a7d08687f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeNotionalAmount_019ead78-9a9d-7ec4-b226-f5a7d08687f1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax_019ead78-9a9d-726f-9666-4f8d06088840" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax_019ead78-9a9d-726f-9666-4f8d06088840" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeGainLossOnDerivativeNet_019ead78-9a9d-752c-91b0-8e5749a2535a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeGainLossOnDerivativeNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosuresLineItems_019ead78-9a9d-75cf-bc1f-7878097028d8" xlink:to="loc_us-gaap_DerivativeGainLossOnDerivativeNet_019ead78-9a9d-752c-91b0-8e5749a2535a" xlink:type="arc" order="6"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails" xlink:type="simple" xlink:href="are-20260630.xsd#StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/StockholdersequityATMcommonstockofferingprogramandForwardEquitySalesAgreementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7b28-b7a8-a07dc88fc4fe" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7b28-b7a8-a07dc88fc4fe" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_019ead78-9a9d-7d36-8ea0-f23a93947e59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7b28-b7a8-a07dc88fc4fe" xlink:to="loc_us-gaap_PlanNameAxis_019ead78-9a9d-7d36-8ea0-f23a93947e59" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019ead78-9a9d-7d36-8ea0-f23a93947e59_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_019ead78-9a9d-7d36-8ea0-f23a93947e59" xlink:to="loc_us-gaap_PlanNameDomain_019ead78-9a9d-7d36-8ea0-f23a93947e59_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_019ead78-9a9d-76c7-9920-f5f35a759ba5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_019ead78-9a9d-7d36-8ea0-f23a93947e59" xlink:to="loc_us-gaap_PlanNameDomain_019ead78-9a9d-76c7-9920-f5f35a759ba5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_ATMCommonStockOfferingProgramEstablishedFebruary2024Member_019ead78-9a9d-7d32-9d94-aa19fd5b3fb6" xlink:href="are-20260630.xsd#are_ATMCommonStockOfferingProgramEstablishedFebruary2024Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_019ead78-9a9d-76c7-9920-f5f35a759ba5" xlink:to="loc_are_ATMCommonStockOfferingProgramEstablishedFebruary2024Member_019ead78-9a9d-7d32-9d94-aa19fd5b3fb6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramAxis_019ead78-9a9d-7345-b288-dcb653fded0e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7b28-b7a8-a07dc88fc4fe" xlink:to="loc_srt_ShareRepurchaseProgramAxis_019ead78-9a9d-7345-b288-dcb653fded0e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019ead78-9a9d-7345-b288-dcb653fded0e_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019ead78-9a9d-7345-b288-dcb653fded0e" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019ead78-9a9d-7345-b288-dcb653fded0e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_019ead78-9a9d-72d9-8ef8-2f40c58f471e" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ShareRepurchaseProgramAxis_019ead78-9a9d-7345-b288-dcb653fded0e" xlink:to="loc_srt_ShareRepurchaseProgramDomain_019ead78-9a9d-72d9-8ef8-2f40c58f471e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_December2025SharesRepurchaseProgramMember_019ead78-9a9d-7ca8-87bb-b1963a97dae3" xlink:href="are-20260630.xsd#are_December2025SharesRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_019ead78-9a9d-72d9-8ef8-2f40c58f471e" xlink:to="loc_are_December2025SharesRepurchaseProgramMember_019ead78-9a9d-7ca8-87bb-b1963a97dae3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019ead78-9a9d-75eb-8b67-cc3f9ae664f4" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_019ead78-9a9d-75eb-8b67-cc3f9ae664f4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramExpirationDate_019ead78-9a9d-7982-a77a-2f61280f7db9" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramExpirationDate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_srt_StockRepurchaseProgramExpirationDate_019ead78-9a9d-7982-a77a-2f61280f7db9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_019ead78-9a9d-7d2b-b6f6-d5382c31fe68" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased_019ead78-9a9d-7d2b-b6f6-d5382c31fe68" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_019ead78-9a9d-703a-87b0-ea64e2cf0c34" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_019ead78-9a9d-703a-87b0-ea64e2cf0c34" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_CommonStockValueAvailableForFutureIssuance_019ead78-9a9d-7aa9-957a-cf6454ef8a76" xlink:href="are-20260630.xsd#are_CommonStockValueAvailableForFutureIssuance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-7ec2-a2f0-690e8e6197c1" xlink:to="loc_are_CommonStockValueAvailableForFutureIssuance_019ead78-9a9d-7aa9-957a-cf6454ef8a76" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/StockholdersequityAOCIDetails" xlink:type="simple" xlink:href="are-20260630.xsd#StockholdersequityAOCIDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/StockholdersequityAOCIDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-75f7-9a61-88d081e87f3a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7ff5-9dc1-d3a5d5256c5a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-75f7-9a61-88d081e87f3a" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7ff5-9dc1-d3a5d5256c5a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-769c-9264-e03983b20fe7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7ff5-9dc1-d3a5d5256c5a" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-769c-9264-e03983b20fe7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-769c-9264-e03983b20fe7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-769c-9264-e03983b20fe7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-769c-9264-e03983b20fe7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7236-b863-a3e3f016b1b6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_019ead78-9a9d-769c-9264-e03983b20fe7" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7236-b863-a3e3f016b1b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7a80-878a-b885a25a0b96" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CurrencySwapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_019ead78-9a9d-7236-b863-a3e3f016b1b6" xlink:to="loc_us-gaap_CurrencySwapMember_019ead78-9a9d-7a80-878a-b885a25a0b96" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7407-8f3c-75ff530e1b2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_019ead78-9a9d-7ff5-9dc1-d3a5d5256c5a" xlink:to="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7407-8f3c-75ff530e1b2d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-7407-8f3c-75ff530e1b2d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7407-8f3c-75ff530e1b2d" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-7407-8f3c-75ff530e1b2d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71c5-bdba-29865df7c64d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingRelationshipDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis_019ead78-9a9d-7407-8f3c-75ff530e1b2d" xlink:to="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71c5-bdba-29865df7c64d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetInvestmentHedgingMember_019ead78-9a9d-72b7-a440-cb45b33ee85a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetInvestmentHedgingMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingRelationshipDomain_019ead78-9a9d-71c5-bdba-29865df7c64d" xlink:to="loc_us-gaap_NetInvestmentHedgingMember_019ead78-9a9d-72b7-a440-cb45b33ee85a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax_019ead78-9a9d-7b2d-900e-5e2f5f055feb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-75f7-9a61-88d081e87f3a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetInvestmentHedgeGainLossBeforeReclassificationAndTax_019ead78-9a9d-7b2d-900e-5e2f5f055feb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_019ead78-9a9d-78f8-9098-e0d1ae0bbe79" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_019ead78-9a9d-75f7-9a61-88d081e87f3a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationGainLossBeforeReclassificationAndTax_019ead78-9a9d-78f8-9098-e0d1ae0bbe79" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SegmentInformationDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SegmentInformationDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SegmentInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7363-b10d-2177b60a9fa5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7363-b10d-2177b60a9fa5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_019ead78-9a9d-74ab-a634-bcdd1e5e5060" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7363-b10d-2177b60a9fa5" xlink:to="loc_srt_ProductOrServiceAxis_019ead78-9a9d-74ab-a634-bcdd1e5e5060" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-74ab-a634-bcdd1e5e5060_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-9a9d-74ab-a634-bcdd1e5e5060" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-74ab-a634-bcdd1e5e5060_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-7b04-ad1b-6178a6cde1ad" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_019ead78-9a9d-74ab-a634-bcdd1e5e5060" xlink:to="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-7b04-ad1b-6178a6cde1ad" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_IncomeFromRentalsMember_019ead78-9a9d-716a-93c0-b4829474040c" xlink:href="are-20260630.xsd#are_IncomeFromRentalsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-7b04-ad1b-6178a6cde1ad" xlink:to="loc_are_IncomeFromRentalsMember_019ead78-9a9d-716a-93c0-b4829474040c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_019ead78-9a9d-7037-846b-9450392d05b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProductAndServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_019ead78-9a9d-7b04-ad1b-6178a6cde1ad" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_019ead78-9a9d-7037-846b-9450392d05b7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7081-9285-61bbb3e8a6fb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7363-b10d-2177b60a9fa5" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7081-9285-61bbb3e8a6fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-7081-9285-61bbb3e8a6fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7081-9285-61bbb3e8a6fb" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-7081-9285-61bbb3e8a6fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7081-9285-61bbb3e8a6fb" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateMember_019ead78-9a9d-7a4d-a733-54025c99af78" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:to="loc_us-gaap_CorporateMember_019ead78-9a9d-7a4d-a733-54025c99af78" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateAndOtherMember_019ead78-9a9d-7748-b3e5-92b1aeedd65b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:to="loc_us-gaap_CorporateAndOtherMember_019ead78-9a9d-7748-b3e5-92b1aeedd65b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-77c7-bea8-6b5e863989e5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-77c7-bea8-6b5e863989e5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019fb05a-9ee0-77cf-bd1b-d31dcb8644b2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7317-bd82-3a60f8115aa6" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019fb05a-9ee0-77cf-bd1b-d31dcb8644b2" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_019ead78-9a9d-7062-ac3c-4295b9d0d9e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_NumberOfOperatingSegments_019ead78-9a9d-7062-ac3c-4295b9d0d9e4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_019ead78-9a9d-799d-b515-7702574a4b09" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_NumberOfReportableSegments_019ead78-9a9d-799d-b515-7702574a4b09" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-72a5-8e80-00a42ec24fe7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-72a5-8e80-00a42ec24fe7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-9a9d-764c-8e32-ea38baed364e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-9a9d-764c-8e32-ea38baed364e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019ead78-9a9d-7e1b-b98f-78fdc01a4aa2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-735b-8344-7b989567eb08" xlink:to="loc_us-gaap_OperatingIncomeLoss_019ead78-9a9d-7e1b-b98f-78fdc01a4aa2" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SegmentInformationReconciliationofOperatingProfitLossfromSegmentstoConsolidatedDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SegmentInformationReconciliationofOperatingProfitLossfromSegmentstoConsolidatedDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SegmentInformationReconciliationofOperatingProfitLossfromSegmentstoConsolidatedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7a5d-a97b-9c41d16b05ab" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7a5d-a97b-9c41d16b05ab" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-76e1-92f0-28b0e58c96c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-7a5d-a97b-9c41d16b05ab" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-76e1-92f0-28b0e58c96c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-76e1-92f0-28b0e58c96c6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-76e1-92f0-28b0e58c96c6" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-76e1-92f0-28b0e58c96c6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-739e-80d1-35b6a6600b0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-76e1-92f0-28b0e58c96c6" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-739e-80d1-35b6a6600b0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-7583-9820-79a2107adcb3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-739e-80d1-35b6a6600b0d" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-7583-9820-79a2107adcb3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019ead78-9a9d-778e-8811-459cbca7b88c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-739e-80d1-35b6a6600b0d" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019ead78-9a9d-778e-8811-459cbca7b88c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-78f1-9c98-0411552a17ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_019ead78-9a9d-78f1-9c98-0411552a17ea" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-9a9d-7f6d-b65c-caa933b1f537" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_019ead78-9a9d-7f6d-b65c-caa933b1f537" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_019ead78-9a9d-7694-bf8b-b2e69a9165ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_OperatingIncomeLoss_019ead78-9a9d-7694-bf8b-b2e69a9165ca" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_019ead78-9a9d-7156-b2b1-2c65059cc283" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_019ead78-9a9d-7156-b2b1-2c65059cc283" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_019ead78-9a9d-750c-8e1b-9caf3568ba67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_InterestExpense_019ead78-9a9d-750c-8e1b-9caf3568ba67" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_019ead78-9a9d-7474-b91f-45139f1521f9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_DepreciationAndAmortization_019ead78-9a9d-7474-b91f-45139f1521f9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfRealEstate_019ead78-9a9d-7880-85a9-2d4ea870bf36" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ImpairmentOfRealEstate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_ImpairmentOfRealEstate_019ead78-9a9d-7880-85a9-2d4ea870bf36" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-9a9d-7323-a3f0-2ba1d2348086" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_019ead78-9a9d-7323-a3f0-2ba1d2348086" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-9a9d-7a86-9488-cc7448497431" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquitySecuritiesFvNiGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_EquitySecuritiesFvNiGainLoss_019ead78-9a9d-7a86-9488-cc7448497431" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-9a9d-712a-b385-02611dd67474" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainsLossesOnExtinguishmentOfDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_GainsLossesOnExtinguishmentOfDebt_019ead78-9a9d-712a-b385-02611dd67474" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_019ead78-9a9d-770a-a2e7-ffaac99fd094" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_019ead78-9a9d-770a-a2e7-ffaac99fd094" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProfitLoss_019ead78-9a9d-7904-9a65-a53a886f94b0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProfitLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-7739-a089-dea43c51af21" xlink:to="loc_us-gaap_ProfitLoss_019ead78-9a9d-7904-9a65-a53a886f94b0" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SegmentInformationReconciliationofInvestmentinRealEstatefromSegmenttoConsolidatedDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SegmentInformationReconciliationofInvestmentinRealEstatefromSegmenttoConsolidatedDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SegmentInformationReconciliationofInvestmentinRealEstatefromSegmenttoConsolidatedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-773a-9007-c30f44e2de8f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-79e7-9c55-5b5adf9b9420" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-773a-9007-c30f44e2de8f" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-79e7-9c55-5b5adf9b9420" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7817-a33f-adcfd2e378ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_019ead78-9a9d-79e7-9c55-5b5adf9b9420" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7817-a33f-adcfd2e378ca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-7817-a33f-adcfd2e378ca_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7817-a33f-adcfd2e378ca" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-7817-a33f-adcfd2e378ca_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_019ead78-9a9d-7f3c-9f67-dedf025b7d85" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_019ead78-9a9d-7817-a33f-adcfd2e378ca" xlink:to="loc_us-gaap_SegmentDomain_019ead78-9a9d-7f3c-9f67-dedf025b7d85" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-7c44-97cc-d783a6004cf9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7f3c-9f67-dedf025b7d85" xlink:to="loc_us-gaap_ReportableSegmentAggregationBeforeOtherOperatingSegmentMember_019ead78-9a9d-7c44-97cc-d783a6004cf9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllOtherSegmentsMember_019ead78-9a9d-7eb8-8b6f-7a59e484993f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllOtherSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_019ead78-9a9d-7f3c-9f67-dedf025b7d85" xlink:to="loc_us-gaap_AllOtherSegmentsMember_019ead78-9a9d-7eb8-8b6f-7a59e484993f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-9a9d-7476-bd7c-0eed76330ea4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RealEstateInvestmentPropertyNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-773a-9007-c30f44e2de8f" xlink:to="loc_us-gaap_RealEstateInvestmentPropertyNet_019ead78-9a9d-7476-bd7c-0eed76330ea4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_AssetsNotAllocatedToSegments_019fb03f-6b3b-7398-91dc-f4c17e6a91dd" xlink:href="are-20260630.xsd#are_AssetsNotAllocatedToSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-773a-9007-c30f44e2de8f" xlink:to="loc_are_AssetsNotAllocatedToSegments_019fb03f-6b3b-7398-91dc-f4c17e6a91dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_019fa9df-4754-7719-9a8b-56639533a1f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_019ead78-9a9d-773a-9007-c30f44e2de8f" xlink:to="loc_us-gaap_Assets_019fa9df-4754-7719-9a8b-56639533a1f1" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.are.com/role/SubsequenteventsDetails" xlink:type="simple" xlink:href="are-20260630.xsd#SubsequenteventsDetails"/>
  <link:definitionLink xlink:role="http://www.are.com/role/SubsequenteventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_019ead78-9a9d-79ba-bad9-57b584f5d327" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_019ead78-9a9d-7205-b201-9ac94a3e13ae" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ead78-9a9d-79ba-bad9-57b584f5d327" xlink:to="loc_us-gaap_SubsequentEventTable_019ead78-9a9d-7205-b201-9ac94a3e13ae" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-7c7f-b69b-1e1736d4a021" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ead78-9a9d-7205-b201-9ac94a3e13ae" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-7c7f-b69b-1e1736d4a021" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-7c7f-b69b-1e1736d4a021_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-7c7f-b69b-1e1736d4a021" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-7c7f-b69b-1e1736d4a021_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-773c-8aa0-c60e98cdf488" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_019ead78-9a9d-7c7f-b69b-1e1736d4a021" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-773c-8aa0-c60e98cdf488" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_019ead78-9a9d-75cc-808c-f21cf232a2ca" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_019ead78-9a9d-773c-8aa0-c60e98cdf488" xlink:to="loc_us-gaap_SubsequentEventMember_019ead78-9a9d-75cc-808c-f21cf232a2ca" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeAxis_019fb030-1828-7e2c-8176-06d262d5b0da" xlink:href="are-20260630.xsd#are_PropertyTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ead78-9a9d-7205-b201-9ac94a3e13ae" xlink:to="loc_are_PropertyTypeAxis_019fb030-1828-7e2c-8176-06d262d5b0da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019fb030-1828-7e2c-8176-06d262d5b0da_default" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_are_PropertyTypeAxis_019fb030-1828-7e2c-8176-06d262d5b0da" xlink:to="loc_are_PropertyTypeDomain_019fb030-1828-7e2c-8176-06d262d5b0da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_PropertyTypeDomain_019fb030-1828-7fef-9aa4-fdfc8c7d6979" xlink:href="are-20260630.xsd#are_PropertyTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_are_PropertyTypeAxis_019fb030-1828-7e2c-8176-06d262d5b0da" xlink:to="loc_are_PropertyTypeDomain_019fb030-1828-7fef-9aa4-fdfc8c7d6979" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_FutureDevelopmentProjectsMember_019fb3da-b278-7756-a3d0-ac770074ada3" xlink:href="are-20260630.xsd#are_FutureDevelopmentProjectsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019fb030-1828-7fef-9aa4-fdfc8c7d6979" xlink:to="loc_are_FutureDevelopmentProjectsMember_019fb3da-b278-7756-a3d0-ac770074ada3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_OperatingPropertiesMember_019fb3da-b278-7e08-a01a-7ff6397187da" xlink:href="are-20260630.xsd#are_OperatingPropertiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_are_PropertyTypeDomain_019fb030-1828-7fef-9aa4-fdfc8c7d6979" xlink:to="loc_are_OperatingPropertiesMember_019fb3da-b278-7e08-a01a-7ff6397187da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fb030-1828-71be-a953-fb0b86f84ec5" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_019ead78-9a9d-7205-b201-9ac94a3e13ae" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fb030-1828-71be-a953-fb0b86f84ec5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fb030-1828-71be-a953-fb0b86f84ec5_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fb030-1828-71be-a953-fb0b86f84ec5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fb030-1828-71be-a953-fb0b86f84ec5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fb030-1828-7899-8b09-106a27a6c175" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis_019fb030-1828-71be-a953-fb0b86f84ec5" xlink:to="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fb030-1828-7899-8b09-106a27a6c175" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_A3825And3875FabianWayMember_019fb3da-b278-72a1-9b1b-8ab3b0b87169" xlink:href="are-20260630.xsd#are_A3825And3875FabianWayMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RealEstateAndAccumulatedDepreciationNameOfPropertyDomain_019fb030-1828-7899-8b09-106a27a6c175" xlink:to="loc_are_A3825And3875FabianWayMember_019fb3da-b278-72a1-9b1b-8ab3b0b87169" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AreaOfRealEstateProperty_019fb030-1828-71bd-8d41-525fc9f319cd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AreaOfRealEstateProperty"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ead78-9a9d-79ba-bad9-57b584f5d327" xlink:to="loc_us-gaap_AreaOfRealEstateProperty_019fb030-1828-71bd-8d41-525fc9f319cd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfPropertyHeldForSale_019fb030-1828-799f-a769-386f9840c903" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ProceedsFromSaleOfPropertyHeldForSale"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ead78-9a9d-79ba-bad9-57b584f5d327" xlink:to="loc_us-gaap_ProceedsFromSaleOfPropertyHeldForSale_019fb030-1828-799f-a769-386f9840c903" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfProperties_019fb030-1828-7166-b00f-d8e2ab28b706" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GainLossOnSaleOfProperties"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_019ead78-9a9d-79ba-bad9-57b584f5d327" xlink:to="loc_us-gaap_GainLossOnSaleOfProperties_019fb030-1828-7166-b00f-d8e2ab28b706" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly"/>
  <link:definitionLink xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_ecd_AllIndividualsMember" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#ecd_AllIndividualsMember"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_MarcE.BindaMember_019ead78-97d5-7433-92e9-26eaa163f12f" xlink:href="are-20260630.xsd#are_MarcE.BindaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_are_MarcE.BindaMember_019ead78-97d5-7433-92e9-26eaa163f12f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_HallieE.KuhnMember_019ef5ae-7e06-7961-bde7-717c81372245" xlink:href="are-20260630.xsd#are_HallieE.KuhnMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_are_HallieE.KuhnMember_019ef5ae-7e06-7961-bde7-717c81372245" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_are_HartColeMember_019efff4-93c1-7bf7-a45f-65535c90e49b" xlink:href="are-20260630.xsd#are_HartColeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_ecd_AllIndividualsMember" xlink:to="loc_are_HartColeMember_019efff4-93c1-7bf7-a45f-65535c90e49b" xlink:type="arc" order="4"/>
  </link:definitionLink>
</link:linkbase>
