The Collaborative International Dictionary of English v.0.48:

Washbowl \Wash"bowl`\, n.
   A basin, or bowl, to hold water for washing one's hands,
   face, etc.
   [1913 Webster]

WordNet (r) 3.0 (2006):

washbowl
    n 1: a bathroom sink that is permanently installed and connected
         to a water supply and drainpipe; where you can wash your
         hands and face; "he ran some water in the basin and
         splashed it on his face" [syn: washbasin, basin,
         washbowl, washstand, lavatory]
    2: a basin for washing the hands (`wash-hand basin' is a British
       expression) [syn: washbasin, handbasin, washbowl,
       lavabo, wash-hand basin]