The Collaborative International Dictionary of English v.0.48:

Fan-tan \Fan"-tan`\ (f[a^]n"t[a^]n`), n. [Chinese (of Canton) in
   an-tan-kun gambling house.]
   1. A Chinese gambling game in which coins or other small
      objects are placed upon a table, usually under a cup, and
      the players bet as to what remainder will be left when the
      sum of the counters is divided by four.
      [Webster 1913 Suppl.]

   2. A game with playing cards in which the cards are played in
      sequences upon the table, the one who first gets rid of
      his cards being the winner.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

fantan
    n 1: a Chinese gambling game; a random number of counters are
         placed under a bowl and you gamble on how many will be left
         (0, 1, 2, or 3 modulo 4) [syn: fantan, fan tan]
    2: a card game in which you play your sevens and other cards in
       sequence in the same suit as the sevens; you win if you are
       the first to use all your cards [syn: fantan, sevens,
       parliament]