The Collaborative International Dictionary of English v.0.48:

Tournament \Tour"na*ment\, n. [OE. turnement, tornement, OF.
   torneiement, tornoiement, F. tournoiement a turning or
   wheeling round. See Tourney.]
   1. A mock fight, or warlike game, formerly in great favor, in
      which a number of combatants were engaged, as an
      exhibition of their address and bravery; hence,
      figuratively, a real battle. "In battle and in
      tourneyment." --Chaucer.
      [1913 Webster]

            With cruel tournament the squadrons join. --Milton.
      [1913 Webster]

   Note: It different from the joust, which was a trial of skill
         between one man and another.
         [1913 Webster]

   2. Any contest of skill in which there are many contestents
      for championship; as, a chess tournament.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tournament
    n 1: a sporting competition in which contestants play a series
         of games to decide the winner [syn: tournament,
         tourney]
    2: a series of jousts between knights contesting for a prize

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "tournament":
   Highland games, Olympiad, Olympic games, Olympics, bout, carousel,
   competition, concours, contest, derby, encounter, engagement,
   event, field day, fight, game, games, go, gymkhana, joust, match,
   matching, meet, meeting, rally, regatta, rencontre, test,
   the Olympics, tilt, tourney, track meet, trial