The Collaborative International Dictionary of English v.0.48:

Cacophony \Ca*coph"o*ny\, n.; pl. Cacophonies. [Gr. ?????????;
   kako`s bad + ???? sound: cf. F. Cacophonie.]
   1. (Rhet.) An uncouth or disagreable sound of words, owing to
      the concurrence of harsh letters or syllables.
      "Cacophonies of all kinds." --Pope.
      [1913 Webster]

   2. (Mus.) A combination of discordant sounds.
      [1913 Webster]

   3. (Med.) An unhealthy state of the voice.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cacophony
    n 1: a loud harsh or strident noise [syn: blare, blaring,
         cacophony, clamor, din]
    2: loud confusing disagreeable sounds