NOUN (3)

1. something or someone seen (especially a notable or unusual sight);
- Example: "the tragic spectacle of cripples trying to escape"

2. an elaborate and remarkable display on a lavish scale;

3. a blunder that makes you look ridiculous; used in the phrase `make a spectacle of' yourself;

The Collaborative International Dictionary of English v.0.48:

Spectacle \Spec"ta*cle\, n. [F., fr. L. spectaculum, fr.
   spectare to look at, to behold, v. intens. fr. specere. See
   Spy.]
   1. Something exhibited to view; usually, something presented
      to view as extraordinary, or as unusual and worthy of
      special notice; a remarkable or noteworthy sight; a show;
      a pageant; a gazingstock.
      [1913 Webster]

            O, piteous spectacle? O, bloody times! --Shak.
      [1913 Webster]

   2. A spy-glass; a looking-glass. [Obs.]
      [1913 Webster]

            Poverty a spectacle is, as thinketh me,
            Through which he may his very friends see.
                                                  --Chaucer.
      [1913 Webster]

   3. pl. An optical instrument consisting of two lenses set in
      a light frame, and worn to assist sight, to obviate some
      defect in the organs of vision, or to shield the eyes from
      bright light.
      [1913 Webster]

   4. pl. Fig.: An aid to the intellectual sight.
      [1913 Webster]

            Shakespeare . . . needed not the spectacles of books
            to read nature.                       --Dryden.
      [1913 Webster]

   Syn: Show; sight; exhibition; representation; pageant.
        [1913 Webster]

WordNet (r) 3.0 (2006):

spectacle
    n 1: something or someone seen (especially a notable or unusual
         sight); "the tragic spectacle of cripples trying to escape"
    2: an elaborate and remarkable display on a lavish scale
    3: a blunder that makes you look ridiculous; used in the phrase
       `make a spectacle of' yourself

Moby Thesaurus II by Grady Ward, 1.0:

164 Moby Thesaurus words for "spectacle":
   Grand Guignol, Passion play, Tom show, amazement, antimasque,
   astonishing thing, astonishment, audience success, ballet, blazon,
   bomb, bravura, brilliancy, broadcast drama, burlesque show,
   charade, cliff hanger, closet drama, comedy drama, cosmorama,
   critical success, curiosity, cyclorama, daring, dash,
   daytime serial, demonstration, dialogue, diorama, display,
   documentary drama, drama, dramalogue, dramatic play,
   dramatic series, dramatics, duodrama, duologue, eclat,
   epic theater, etalage, event, exception, exhibit, exhibition,
   exhibitionism, experimental theater, exposition, extravaganza,
   eyeglasses, failure, false front, fanfaronade, figure, flair,
   flaunt, flaunting, flop, flourish, fool, gasser, gazingstock,
   georama, giveaway, glasses, happening, histrionics, hit, hit show,
   improvisational drama, legitimate drama, light show, manifestation,
   marvel, marvelment, masque, melodrama, minstrel show, miracle,
   miracle play, monodrama, monologue, morality, morality play,
   music drama, musical revue, myriorama, mystery, mystery play,
   nonesuch, opera, pageant, pageantry, panel show, panorama,
   pantomime, parade, pastoral, pastoral drama, performance,
   phantasmagoria, phenomenon, piece, play, playlet, pomp,
   presentation, problem play, prodigy, psychedelic show, psychodrama,
   quite a thing, quiz show, radio drama, rarity, representation,
   review, revue, sensation, sensational play, serial, sham,
   shifting scene, show, showing-off, sight, sitcom, situation comedy,
   sketch, skit, soap, soap opera, sociodrama, something else, specs,
   spectacles, splash, splurge, stage play, stage show, staginess,
   straight drama, stunner, success, suspense drama, tableau,
   tableau vivant, talk show, teleplay, television drama,
   television play, theater of cruelty, theatrics, total theater,
   variety show, vaudeville, vaudeville show, vaunt, vehicle, wonder,
   wonderful thing, wonderment, word-of-mouth success, work