Commutation

1. 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.
2. n. A passing from one state to another; change; alteration; mutation.
3. n. The act of giving one thing for another; barter; exchange.
4. 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.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.