<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd http://xbrl.org/2005/xbrldt http://www.xbrl.org/2005/xbrldt-2005.xsd" xmlns:cik0000783740="http://www.MFS.com/20260531">
	<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/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: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://www.xbrl.org/2009/arcrole/dep-concept-deprecatedConcept" xlink:type="simple" xlink:href="http://www.xbrl.org/lrr/arcrole/deprecated-2009-12-16.xsd#dep-concept-deprecatedConcept" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable3" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable3" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable5" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable5" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable7" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable7" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable9" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable9" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable11" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable11" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable13" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable13" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable15" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable15" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable17" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable17" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable19" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable19" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable21" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable21" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable23" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable23" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable25" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable25" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable27" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable27" />
	<link:roleRef roleURI="http://www.MFS.com/20260531/role/RRRiskTable29" xlink:type="simple" xlink:href="c485bpos-20260925.xsd#RRRiskTable29" />
	<link:roleRef roleURI="http://xbrl.sec.gov/oef/role/SeriesOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#SeriesOnly" />
	<link:roleRef roleURI="http://xbrl.sec.gov/oef/role/ClassOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ClassOnly" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/ShareholderFeesData" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#ShareholderFeesData" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/OperatingExpensesData" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#OperatingExpensesData" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#PerformanceMeasureOnly" />
	<link:roleRef roleURI="http://xbrl.sec.gov/rr/role/RiskOnly" xlink:type="simple" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#RiskOnly" />
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/SeriesOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/dei/2025/dei-2025.xsd#dei_EntityDomain" xlink:label="EntityDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002506Member" xlink:label="S000002506Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002506Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000050658Member" xlink:label="S000050658Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000050658Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000050659Member" xlink:label="S000050659Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000050659Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000054892Member" xlink:label="S000054892Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000054892Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000050660Member" xlink:label="S000050660Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000050660Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002510Member" xlink:label="S000002510Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002510Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002512Member" xlink:label="S000002512Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002512Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002514Member" xlink:label="S000002514Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002514Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002515Member" xlink:label="S000002515Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002515Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002516Member" xlink:label="S000002516Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002516Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002517Member" xlink:label="S000002517Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002517Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000068882Member" xlink:label="S000068882Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000068882Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000045806Member" xlink:label="S000045806Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000045806Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_S000002507Member" xlink:label="S000002507Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="EntityDomain" xlink:to="S000002507Member" order="14.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/oef/role/ClassOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_ShareClassDomain" xlink:label="ShareClassDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006838Member" xlink:label="C000006838Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006838Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006843Member" xlink:label="C000006843Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006843Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006844Member" xlink:label="C000006844Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006844Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006845Member" xlink:label="C000006845Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006845Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006847Member" xlink:label="C000006847Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006847Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006849Member" xlink:label="C000006849Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006849Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006850Member" xlink:label="C000006850Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006850Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006839Member" xlink:label="C000006839Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006839Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000231058Member" xlink:label="C000231058Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000231058Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160020Member" xlink:label="C000160020Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160020Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160021Member" xlink:label="C000160021Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160021Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160022Member" xlink:label="C000160022Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160022Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160023Member" xlink:label="C000160023Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160023Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160024Member" xlink:label="C000160024Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160024Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160025Member" xlink:label="C000160025Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160025Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160026Member" xlink:label="C000160026Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160026Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160027Member" xlink:label="C000160027Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160027Member" order="17.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160028Member" xlink:label="C000160028Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160028Member" order="18.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160029Member" xlink:label="C000160029Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160029Member" order="19.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160030Member" xlink:label="C000160030Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160030Member" order="20.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160031Member" xlink:label="C000160031Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160031Member" order="21.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160032Member" xlink:label="C000160032Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160032Member" order="22.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160033Member" xlink:label="C000160033Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160033Member" order="23.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160034Member" xlink:label="C000160034Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160034Member" order="24.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160035Member" xlink:label="C000160035Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160035Member" order="25.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160036Member" xlink:label="C000160036Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160036Member" order="26.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160037Member" xlink:label="C000160037Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160037Member" order="27.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172715Member" xlink:label="C000172715Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172715Member" order="28.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172716Member" xlink:label="C000172716Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172716Member" order="29.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172717Member" xlink:label="C000172717Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172717Member" order="30.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172718Member" xlink:label="C000172718Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172718Member" order="31.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172719Member" xlink:label="C000172719Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172719Member" order="32.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172720Member" xlink:label="C000172720Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172720Member" order="33.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172721Member" xlink:label="C000172721Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172721Member" order="34.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172722Member" xlink:label="C000172722Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172722Member" order="35.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000172723Member" xlink:label="C000172723Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000172723Member" order="36.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160038Member" xlink:label="C000160038Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160038Member" order="37.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160039Member" xlink:label="C000160039Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160039Member" order="38.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160040Member" xlink:label="C000160040Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160040Member" order="39.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160041Member" xlink:label="C000160041Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160041Member" order="40.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160042Member" xlink:label="C000160042Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160042Member" order="41.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160043Member" xlink:label="C000160043Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160043Member" order="42.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160044Member" xlink:label="C000160044Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160044Member" order="43.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160045Member" xlink:label="C000160045Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160045Member" order="44.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000160046Member" xlink:label="C000160046Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000160046Member" order="45.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006887Member" xlink:label="C000006887Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006887Member" order="46.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006892Member" xlink:label="C000006892Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006892Member" order="47.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006893Member" xlink:label="C000006893Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006893Member" order="48.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006894Member" xlink:label="C000006894Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006894Member" order="49.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006896Member" xlink:label="C000006896Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006896Member" order="50.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006898Member" xlink:label="C000006898Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006898Member" order="51.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006899Member" xlink:label="C000006899Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006899Member" order="52.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006888Member" xlink:label="C000006888Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006888Member" order="53.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000231060Member" xlink:label="C000231060Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000231060Member" order="54.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006904Member" xlink:label="C000006904Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006904Member" order="55.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006905Member" xlink:label="C000006905Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006905Member" order="56.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006906Member" xlink:label="C000006906Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006906Member" order="57.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006907Member" xlink:label="C000006907Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006907Member" order="58.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071424Member" xlink:label="C000071424Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071424Member" order="59.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071425Member" xlink:label="C000071425Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071425Member" order="60.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071426Member" xlink:label="C000071426Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071426Member" order="61.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071427Member" xlink:label="C000071427Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071427Member" order="62.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071428Member" xlink:label="C000071428Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071428Member" order="63.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006911Member" xlink:label="C000006911Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006911Member" order="64.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006916Member" xlink:label="C000006916Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006916Member" order="65.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006917Member" xlink:label="C000006917Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006917Member" order="66.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006918Member" xlink:label="C000006918Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006918Member" order="67.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006920Member" xlink:label="C000006920Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006920Member" order="68.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006922Member" xlink:label="C000006922Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006922Member" order="69.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006923Member" xlink:label="C000006923Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006923Member" order="70.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006912Member" xlink:label="C000006912Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006912Member" order="71.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000231061Member" xlink:label="C000231061Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000231061Member" order="72.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006924Member" xlink:label="C000006924Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006924Member" order="73.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006929Member" xlink:label="C000006929Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006929Member" order="74.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006930Member" xlink:label="C000006930Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006930Member" order="75.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006931Member" xlink:label="C000006931Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006931Member" order="76.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006933Member" xlink:label="C000006933Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006933Member" order="77.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006935Member" xlink:label="C000006935Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006935Member" order="78.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006936Member" xlink:label="C000006936Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006936Member" order="79.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006925Member" xlink:label="C000006925Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006925Member" order="80.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000195683Member" xlink:label="C000195683Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000195683Member" order="81.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006937Member" xlink:label="C000006937Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006937Member" order="82.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006938Member" xlink:label="C000006938Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006938Member" order="83.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006939Member" xlink:label="C000006939Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006939Member" order="84.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006940Member" xlink:label="C000006940Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006940Member" order="85.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071431Member" xlink:label="C000071431Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071431Member" order="86.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071432Member" xlink:label="C000071432Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071432Member" order="87.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071433Member" xlink:label="C000071433Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071433Member" order="88.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071430Member" xlink:label="C000071430Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071430Member" order="89.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000034484Member" xlink:label="C000034484Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000034484Member" order="90.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006941Member" xlink:label="C000006941Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006941Member" order="91.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006942Member" xlink:label="C000006942Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006942Member" order="92.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006943Member" xlink:label="C000006943Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006943Member" order="93.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006944Member" xlink:label="C000006944Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006944Member" order="94.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071434Member" xlink:label="C000071434Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071434Member" order="95.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071435Member" xlink:label="C000071435Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071435Member" order="96.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071436Member" xlink:label="C000071436Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071436Member" order="97.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000071437Member" xlink:label="C000071437Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000071437Member" order="98.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000034485Member" xlink:label="C000034485Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000034485Member" order="99.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220109Member" xlink:label="C000220109Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220109Member" order="100.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220112Member" xlink:label="C000220112Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220112Member" order="101.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220111Member" xlink:label="C000220111Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220111Member" order="102.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220110Member" xlink:label="C000220110Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220110Member" order="103.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220113Member" xlink:label="C000220113Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220113Member" order="104.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220108Member" xlink:label="C000220108Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220108Member" order="105.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220107Member" xlink:label="C000220107Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220107Member" order="106.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000220106Member" xlink:label="C000220106Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000220106Member" order="107.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142775Member" xlink:label="C000142775Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142775Member" order="108.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142776Member" xlink:label="C000142776Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142776Member" order="109.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142777Member" xlink:label="C000142777Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142777Member" order="110.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142778Member" xlink:label="C000142778Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142778Member" order="111.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142779Member" xlink:label="C000142779Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142779Member" order="112.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142780Member" xlink:label="C000142780Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142780Member" order="113.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142781Member" xlink:label="C000142781Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142781Member" order="114.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000142782Member" xlink:label="C000142782Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000142782Member" order="115.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000195688Member" xlink:label="C000195688Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000195688Member" order="116.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006851Member" xlink:label="C000006851Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006851Member" order="117.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006856Member" xlink:label="C000006856Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006856Member" order="118.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006857Member" xlink:label="C000006857Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006857Member" order="119.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006858Member" xlink:label="C000006858Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006858Member" order="120.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006860Member" xlink:label="C000006860Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006860Member" order="121.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006862Member" xlink:label="C000006862Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006862Member" order="122.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006863Member" xlink:label="C000006863Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006863Member" order="123.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000006852Member" xlink:label="C000006852Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000006852Member" order="124.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_C000231059Member" xlink:label="C000231059Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="ShareClassDomain" xlink:to="C000231059Member" order="125.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/PerformanceMeasureOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_PerformanceMeasureDomain" xlink:label="PerformanceMeasureDomain" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_StandardPoors500StockIndex31Member" xlink:label="StandardPoors500StockIndex31Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="StandardPoors500StockIndex31Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MFSAggressiveGrowthAllocationFundBlendedIndex32Member" xlink:label="MFSAggressiveGrowthAllocationFundBlendedIndex32Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MFSAggressiveGrowthAllocationFundBlendedIndex32Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell3000Index33Member" xlink:label="Russell3000Index33Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell3000Index33Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell1000GrowthIndex34Member" xlink:label="Russell1000GrowthIndex34Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell1000GrowthIndex34Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell3000Index35Member" xlink:label="Russell3000Index35Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell3000Index35Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell2000Index36Member" xlink:label="Russell2000Index36Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell2000Index36Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell3000Index37Member" xlink:label="Russell3000Index37Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell3000Index37Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_RussellMidcapIndex38Member" xlink:label="RussellMidcapIndex38Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="RussellMidcapIndex38Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell3000Index39Member" xlink:label="Russell3000Index39Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell3000Index39Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Russell1000ValueIndex310Member" xlink:label="Russell1000ValueIndex310Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="Russell1000ValueIndex310Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_BloombergUSAggregateBondIndex311Member" xlink:label="BloombergUSAggregateBondIndex311Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="BloombergUSAggregateBondIndex311Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MFSConservativeAllocationFundBlendedIndex312Member" xlink:label="MFSConservativeAllocationFundBlendedIndex312Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MFSConservativeAllocationFundBlendedIndex312Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIEmergingMarketsIndexnetdiv313Member" xlink:label="MSCIEmergingMarketsIndexnetdiv313Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIEmergingMarketsIndexnetdiv313Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_StandardPoors500StockIndex314Member" xlink:label="StandardPoors500StockIndex314Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="StandardPoors500StockIndex314Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MFSGrowthAllocationFundBlendedIndex315Member" xlink:label="MFSGrowthAllocationFundBlendedIndex315Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MFSGrowthAllocationFundBlendedIndex315Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIAllCountryWorldex-USIndexnetdiv316Member" xlink:label="MSCIAllCountryWorldex-USIndexnetdiv316Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIAllCountryWorldex-USIndexnetdiv316Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIAllCountryWorldex-USIndexnetdiv317Member" xlink:label="MSCIAllCountryWorldex-USIndexnetdiv317Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIAllCountryWorldex-USIndexnetdiv317Member" order="17.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIAllCountryWorldex-USGrowthIndexnetdiv318Member" xlink:label="MSCIAllCountryWorldex-USGrowthIndexnetdiv318Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIAllCountryWorldex-USGrowthIndexnetdiv318Member" order="18.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv319Member" xlink:label="MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv319Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv319Member" order="19.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv320Member" xlink:label="MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv320Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv320Member" order="20.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv321Member" xlink:label="MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv321Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIEAFEEuropeAustralasiaFarEastIndexnetdiv321Member" order="21.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv322Member" xlink:label="MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv322Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MSCIEAFEEuropeAustralasiaFarEastValueIndexnetdiv322Member" order="22.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_StandardPoors500StockIndex323Member" xlink:label="StandardPoors500StockIndex323Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="StandardPoors500StockIndex323Member" order="23.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_ICEBofA0-3MonthUSTreasuryBillIndex324Member" xlink:label="ICEBofA0-3MonthUSTreasuryBillIndex324Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="ICEBofA0-3MonthUSTreasuryBillIndex324Member" order="24.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_StandardPoors500StockIndex325Member" xlink:label="StandardPoors500StockIndex325Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="StandardPoors500StockIndex325Member" order="25.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MFSModerateAllocationFundBlendedIndex326Member" xlink:label="MFSModerateAllocationFundBlendedIndex326Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="PerformanceMeasureDomain" xlink:to="MFSModerateAllocationFundBlendedIndex326Member" order="26.0" />
	</link:definitionLink>
	<link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/rr/role/RiskOnly">
		<link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/oef/2025/oef-2025.xsd#oef_AllRisksMember" xlink:label="AllRisksMember" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_PrincipalRisks2Member" xlink:label="PrincipalRisks2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PrincipalRisks2Member" order="1.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_AllocationRisk2Member" xlink:label="AllocationRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="AllocationRisk2Member" order="2.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_UnderlyingFundsRisk2Member" xlink:label="UnderlyingFundsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="UnderlyingFundsRisk2Member" order="3.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_InvestmentSelectionRisk2Member" xlink:label="InvestmentSelectionRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InvestmentSelectionRisk2Member" order="4.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_EquityMarketRiskCompanyRisk2Member" xlink:label="EquityMarketRiskCompanyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="EquityMarketRiskCompanyRisk2Member" order="5.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_GrowthCompanyRisk2Member" xlink:label="GrowthCompanyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="GrowthCompanyRisk2Member" order="6.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_ValueCompanyRisk2Member" xlink:label="ValueCompanyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ValueCompanyRisk2Member" order="7.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_DebtMarketRisk2Member" xlink:label="DebtMarketRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="DebtMarketRisk2Member" order="8.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_InterestRateRisk2Member" xlink:label="InterestRateRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InterestRateRisk2Member" order="9.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_CreditRisk2Member" xlink:label="CreditRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CreditRisk2Member" order="10.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_PrepaymentExtensionRisk2Member" xlink:label="PrepaymentExtensionRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="PrepaymentExtensionRisk2Member" order="11.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Inflation-AdjustedDebtInstrumentsRisk2Member" xlink:label="Inflation-AdjustedDebtInstrumentsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Inflation-AdjustedDebtInstrumentsRisk2Member" order="12.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_FocusRisk2Member" xlink:label="FocusRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="FocusRisk2Member" order="13.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_ForeignRisk2Member" xlink:label="ForeignRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="ForeignRisk2Member" order="14.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_EmergingMarketsRisk2Member" xlink:label="EmergingMarketsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="EmergingMarketsRisk2Member" order="15.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_CurrencyRisk2Member" xlink:label="CurrencyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CurrencyRisk2Member" order="16.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_RealEstate-RelatedInvestmentRisk2Member" xlink:label="RealEstate-RelatedInvestmentRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="RealEstate-RelatedInvestmentRisk2Member" order="17.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Commodity-RelatedInvestmentsRisk2Member" xlink:label="Commodity-RelatedInvestmentsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Commodity-RelatedInvestmentsRisk2Member" order="18.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_When-IssuedDelayedDeliveryandForwardCommitmentTransactionRisk2Member" xlink:label="When-IssuedDelayedDeliveryandForwardCommitmentTransactionRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="When-IssuedDelayedDeliveryandForwardCommitmentTransactionRisk2Member" order="19.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_DerivativesRisk2Member" xlink:label="DerivativesRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="DerivativesRisk2Member" order="20.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_LeveragingRisk2Member" xlink:label="LeveragingRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="LeveragingRisk2Member" order="21.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_CounterpartyandThirdPartyRisk2Member" xlink:label="CounterpartyandThirdPartyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="CounterpartyandThirdPartyRisk2Member" order="22.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_LiquidityRisk2Member" xlink:label="LiquidityRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="LiquidityRisk2Member" order="23.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_LargeShareholderRisk2Member" xlink:label="LargeShareholderRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="LargeShareholderRisk2Member" order="24.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_InvestmentStrategyRisk2Member" xlink:label="InvestmentStrategyRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="InvestmentStrategyRisk2Member" order="25.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_Non-DiversificationRisk2Member" xlink:label="Non-DiversificationRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="Non-DiversificationRisk2Member" order="26.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_SmallCapRisk2Member" xlink:label="SmallCapRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="SmallCapRisk2Member" order="27.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_REITsRisk2Member" xlink:label="REITsRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="REITsRisk2Member" order="28.0" />
		<link:loc xlink:type="locator" xlink:href="c485bpos-20260925.xsd#cik0000783740_MidCapRisk2Member" xlink:label="MidCapRisk2Member" />
		<link:definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="AllRisksMember" xlink:to="MidCapRisk2Member" order="29.0" />
	</link:definitionLink>
</link:linkbase>