Commutation

n.
  1. A passing from one state to another; change; alteration; mutation.
  2. The act of giving one thing for another; barter; exchange.
  3. (Law) 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. 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.
  5. regular travel from a place of residence to a place where one's daily work is performed; commuting. Most often, such travel is performed between a suburb and a nearby city.
  6. Angle of commutation (Astron.),
    the difference of the geocentric longitudes of the sun and a planet.
    Commutation of tithes ,
    the substitution of a regular payment, chargeable to the land, for the annual tithes in kind.
    Commutation ticket ,
    a ticket, as for transportation, which is the evidence of a contract for service at a reduced rate. See 2d Commute, 2.