The Collaborative International Dictionary of English v.0.48:

Blow-out \Blow"-out`\, n.
   The cleaning of the flues of a boiler from scale, etc., by a
   blast of steam.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

blowout \blowout\ n.
   1. a gay or lavish festivity. [colloq.]

   Syn: gala, gala affair, jamboree.
        [WordNet 1.5]

   2. the sudden deflation of an inflatable tire due to a
      puncture or rupture, often accompanied by a bang.
      [PJC]

   3. the sudden escape of gas or liquid confined under
      pressure, such as in a gas or oil well, or in a system
      containing pressurized air or steam.
      [PJC]

WordNet (r) 3.0 (2006):

blowout
    n 1: an easy victory [syn: runaway, blowout, romp,
         laugher, shoo-in, walkaway]
    2: a sudden malfunction of a part or apparatus; "the right front
       tire had a blowout"; "as a result of the blowout we lost all
       the lights"
    3: a gay festivity [syn: gala, gala affair, jamboree,
       blowout]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "blowout":
   Kaffeeklatsch, Lucullan feast, Mardi Gras, Saturnalia, backfire,
   ball, bang, banquet, bash, bean-feast, beano, blast, blow, blowup,
   boom, burst, carnival, cocktail party, coffee klatch,
   costume party, detonation, dinner, dinner party, discharge,
   disgorgement, do, donation party, ejaculation, emission,
   entertainment, eructation, eruption, explosion, expulsion,
   extravasation, fair, feast, festal board, festival,
   festive occasion, festivity, fete, field day, fiesta, flare, flash,
   fulguration, fulmination, gala, gala affair, gala day,
   garden party, great doings, groaning board, hen party, high jinks,
   house party, house-raising, housewarming, jamboree, jet, kermis,
   lawn party, mask, masque, masquerade, masquerade party, outburst,
   outpour, party, picnic, report, shindig, shindy, shower, smoker,
   spout, spurt, squirt, stag, stag party, surprise party, waygoose,
   wayzgoose