1. (n.) A passing from one state to another; change; alteration; mutation.

2. (n.) The act of giving one thing for another; barter; exchange.

3. (n.) The change of a penalty or punishment by the pardoning power of the State; as, the commutation of a sentence of death to banishment or imprisonment.

4. (n.) A substitution, as of a less thing for a greater, esp. a substitution of one form of payment for another, or one payment for many, or a specific sum of money for conditional payments or allowances; as, commutation of tithes; commutation of fares; commutation of copyright; commutation of rations.

agency alternation amends atonement balancing battledore and shuttlecock change compensation cooperation counteraction counterbalancing counterchange course cross fire crossing delegation deputation deputyship displacement exchange expiation give-and-take globe-trotting going indemnification indemnity interchange intermutation interplay journeying lex talionis locomotion measure for measure motion movement moving mutual admiration mutual support mutual transfer mutuality offsetting passage permutation power of attorney progress quid pro quo reciprocality reciprocation reciprocity recompense rectification redress reparation repayment replacement representation restitution retaliation revenge satisfaction something for something subrogation substitution supersedence superseding supersedure supersession supplantation supplanting supplantment switch tit for tat tourism touristry traject trajet transit transposal transposition travel traveling vicariousness