WordNet (r) 3.0 (2006):

comfort station
    n 1: a toilet that is available to the public [syn: public
         toilet, comfort station, public convenience,
         convenience, public lavatory, restroom, toilet
         facility, wash room]

Moby Thesaurus II by Grady Ward, 1.0:

25 Moby Thesaurus words for "comfort station":
   WC, backhouse, basement, bathroom, can, closet, convenience,
   crapper, earth closet, head, john, johnny, johnny house, latrine,
   lavatory, necessary, outhouse, powder room, privy, rest room,
   toilet, toilet room, urinal, washroom, water closet