commutation in WordNet English dictionary

1. the travel of a commuter
   commutation  commuting 
   
2. (law) the reduction in severity of a punishment imposed by law
   commutation  re-sentencing 
   
3. the act of putting one thing or person in the place of another: "he sent Smith in for Jones but the substitution came too late to help"
   substitution  exchange  commutation 
   
4. a warrant substituting a lesser punishment for a greater one
   commutation