Source : Webster's Revised Unabridged Dictionary (1913)

Loo \Loo\, n. [For older lanterloo, F. lanturelu, lanturlu, name
   of the game; orig., the refrain of a vaudeville.]
   (a) An old game played with five, or three, cards dealt to
       each player from a full pack. When five cards are used
       the highest card is the knave of clubs or (if so agreed
       upon) the knave of trumps; -- formerly called
       {lanterloo}.
   (b) A modification of the game of ``all fours'' in which the
       players replenish their hands after each round by drawing
       each a card from the pack.

Loo \Loo\, v. t. [imp. & p. p. {Looed}; p. pr. & vb. n.
   {Looing}.]
   To beat in the game of loo by winning every trick. [Written
   also {lu}.] --Goldsmith.

Source : WordNet®

loo
     n : a toilet in England [syn: {water closet}, {closet}, {W.C.}]