Source : WordNet®

tic-tac-toe
     n : a game in which two players alternately put crosses and
         circles in one of the compartments of a 3-by-3 board; the
         object is to get a row of three crosses or three circles
         before the opponent does [syn: {ticktacktoe}, {ticktacktoo},
          {tick-tack-toe}, {tit-tat-toe}, {noughts and crosses}]