[com.mu.ta.tion] n [ME, fr. MF, fr. L commutation-, commutatio, fr. commutare] (15c) 1: exchange, trade
2: replacement; specif: a substitution of one form of payment or charge for another
3: a change of a legal penalty or punishment to a lesser one
4: an act or process of commuting
5: the action of commutating