Obsolescence rhymes with:
adolescence, coalescence, convalescence, adolescence, coalescence, convalescence, acquiescence, adolescence, coalescence, convalescence, essence, evanescence, luminescence, phosphorescence, quintessence, senescence
adolescence, coalescence, convalescence, adolescence, coalescence, convalescence, acquiescence, adolescence, coalescence, convalescence, essence, evanescence, luminescence, phosphorescence, quintessence, senescence