The Collaborative International Dictionary of English v.0.48:

Bout \Bout\, n. [A different spelling and application of bought
   bend.]
   [1913 Webster]
   1. As much of an action as is performed at one time; a going
      and returning, as of workmen in reaping, mowing, etc.; a
      turn; a round.
      [1913 Webster]

            In notes with many a winding bout
            Of linked sweetness long drawn out.   --Milton.
      [1913 Webster]

            The prince . . . has taken me in his train, so that
            I am in no danger of starving for this bout.
                                                  --Goldsmith.
      [1913 Webster]

   2. A conflict; contest; attempt; trial; a set-to at anything;
      as, a fencing bout; a drinking bout.
      [1913 Webster]

            The gentleman will, for his honor's sake, have one
            bout with you; he can not by the duello avoid it.
                                                  --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

bout
    n 1: (sports) a division during which one team is on the
         offensive [syn: turn, bout, round]
    2: a period of illness; "a bout of fever"; "a bout of
       depression"
    3: a contest or fight (especially between boxers or wrestlers)
    4: an occasion for excessive eating or drinking; "they went on a
       bust that lasted three days" [syn: bust, tear, binge,
       bout]

Moby Thesaurus II by Grady Ward, 1.0:

127 Moby Thesaurus words for "bout":
   Chinese boxing, Olympic games, Olympics, arsis, bacchanal,
   bacchanalia, bacchanalian, bat, beat, bender, binge, boxing,
   boxing match, bust, carousal, carouse, celebration, chance, circle,
   circuit, close fighting, compotation, concours, contest, course,
   cycle, debauch, decathlon, derby, diastole, double-header, doubles,
   downbeat, drinking bout, drunk, drunken carousal, duel, encounter,
   engagement, escapade, event, fight, fighting, fisticuffs, fling,
   foursome, game, games, games of chance, go, guzzle, gymkhana,
   infighting, inning, innings, jag, joust, lark, match, matching,
   meet, meeting, occasion, opportunity, orgy, pentathlon, period,
   place, play, play-off, ploy, potation, prizefight, prizefighting,
   pub-crawl, pugilism, pulse, race, rally, randan, randy, relief,
   rencontre, revel, revolution, rotation, round, runoff, savate, say,
   series, session, set-to, shadowboxing, shift, singles, spar, spell,
   sport, spree, stint, struggle, symposium, systole, tear, test,
   the clinches, the fights, the ring, thesis, threesome, tilt, time,
   time at bat, toot, tour, tournament, tourney, trial, trick, turn,
   twosome, upbeat, wassail, whack, wheel, wingding