The Collaborative International Dictionary of English v.0.48:

Breakdown \Break"down`\, n.
   1. The act or result of breaking down, as of a carriage;
      downfall.
      [1913 Webster]

   2.
      (a) A noisy, rapid, shuffling dance engaged in
          competitively by a number of persons or pairs in
          succession, as among the colored people of the
          Southern United States, and so called, perhaps,
          because the exercise is continued until most of those
          who take part in it break down.
      (b) Any rude, noisy dance performed by shuffling the feet,
          usually by one person at a time. [U.S.]
          [1913 Webster]

                Don't clear out when the quadrilles are over,
                for we are going to have a breakdown to wind up
                with.                             --New Eng.
                                                  Tales.
          [1913 Webster]

WordNet (r) 3.0 (2006):

breakdown
    n 1: the act of disrupting an established order so it fails to
         continue; "the social dislocations resulting from
         government policies"; "his warning came after the breakdown
         of talks in London" [syn: dislocation, breakdown]
    2: a mental or physical breakdown [syn: breakdown, crack-up]
    3: a cessation of normal operation; "there was a power
       breakdown" [syn: breakdown, equipment failure]
    4: an analysis into mutually exclusive categories [syn:
       breakdown, partitioning]

Moby Thesaurus II by Grady Ward, 1.0:

125 Moby Thesaurus words for "breakdown":
   analysis, analyzation, anatomizing, anatomy, assay, assaying,
   bankruptcy, bloodless revolution, bouleversement, breakage,
   breaking down, breaking up, breakup, cataclysm, catastrophe, cave,
   cave-in, circulatory collapse, classification, clean slate,
   clean sweep, collapse, comedown, computer revolution, convulsion,
   counterrevolution, crack-up, crackup, crash, crippling, cropper,
   damage, debacle, decomposition, deflation, destruction, detailing,
   detriment, diaeresis, dilapidation, disablement, disaster,
   disrepair, dissection, distillation, division, docimasy, downfall,
   draining, encroachment, exhaustedness, exhaustion, failure, fall,
   foundering, fractionation, gravimetric analysis, harm, hobbling,
   hurt, hurting, impairment, incapacitation, infringement, injury,
   inroad, itemization, loss, maiming, mayhem, mischief, mutilation,
   nervous breakdown, nervous exhaustion, nervous prostration,
   neurasthenia, nose dive, overthrow, overturn, palace revolution,
   pratfall, prostration, proximate analysis, quantitative analysis,
   radical change, reduction to elements, resolution, review, revolt,
   revolution, revolutionary war, revulsion, ruin, ruination,
   ruinousness, run-down, sabotage, scathe, segmentation,
   semimicroanalysis, separation, shipwreck, sickening, smash,
   smashup, spasm, spoiling, striking alteration, stumble,
   subdivision, subversion, sweeping change, tabula rasa, tailspin,
   technological revolution, total change, total loss, transilience,
   tumble, upset, violent change, washout, weakening, wrack, wreck