The Collaborative International Dictionary of English v.0.48:

Commuter \Com*mut"er\ (k[o^]m*m[=u]"t[~e]r), n.
   One who commutes; especially, one who commutes in traveling.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Commuter \Com*mut"er\ (k[o^]m*m[=u]"t[~e]r), a.
   of or pertaining to commuting, in the sense of traveling;
   used for commuting; as, a commuter airline.
   [PJC]

WordNet (r) 3.0 (2006):

commuter
    n 1: a passenger train that is ridden primarily by passengers
         who travel regularly from one place to another [syn:
         commuter, commuter train]
    2: someone who travels regularly from home in a suburb to work
       in a city