lav

from WordNet (r) 3.0 (2006)

lav
    n 1: a room or building equipped with one or more toilets [syn:
         {toilet}, {lavatory}, {lav}, {can}, {john}, {privy},
         {bathroom}]

from The Collaborative International Dictionary of English v.0.48

lav \lav\ n. [by truncation of lavatory.]
   Same as {lavatory}[5]; -- a shortened form of the word.
   [informal]

   Syn: toilet, lavatory, can, facility, john, privy, bathroom.
        [WordNet 1.5]