commutation (n.)youdaoicibaDictYouDict[commutation 词源字典]
mid-15c., from Old French commutacion "change, transformation, exchange, barter" (13c., Modern French commutation), from Latin commutationem (nominative commutatio) "a change, alteration," noun of action from past participle stem of commutare "to change, alter entirely" (see commute (v.)).[commutation etymology, commutation origin, 英语词源]