The Collaborative International Dictionary of English v.0.48:

Toby \To"by\, n.; pl. -bies. [Perh. from the proper name.]
   A small jug, pitcher, or mug, generally used for ale, shaped
   somewhat like a stout man, with a cocked hat forming the
   brim.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

toby
    n 1: a drinking mug in the shape of a stout man wearing a three-
         cornered hat [syn: toby, toby jug, toby fillpot jug]