Polyphonic

from WordNet (r) 3.0 (2006)

polyphonic
    adj 1: having two or more phonetic values; "polyphonic letters
           such as `a'"
    2: of or relating to or characterized by polyphony; "polyphonic
       traditions of the baroque" [syn: {polyphonic}, {polyphonous}]
    3: having two or more independent but harmonically related
       melodic parts sounding together [syn: {polyphonic},
       {contrapuntal}] [ant: {monophonic}]

from The Collaborative International Dictionary of English v.0.48

Polyphonic \Pol`y*phon"ic\, a. [Gr. ?; poly`s many + ? sound:
   cf. F. polyphone.]
   1. Having a multiplicity of sounds.
      [1913 Webster]

   2. Characterized by polyphony; as, Assyrian polyphonic
      characters.
      [1913 Webster]

   3. (Mus.) Consisting of several tone series, or melodic
      parts, progressing simultaneously according to the laws of
      counterpoint; contrapuntal; as, a polyphonic composition;
      -- opposed to {homophonic}, or {monodic}.
      [1913 Webster]