mid-15c., commutacioun, "act of giving one thing for another," 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.)).
From c. 1500 as "a passage from one state to another;" 1590s as "act of substituting one thing for another."
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