Source : Webster's Revised Unabridged Dictionary (1913)

Polysynthetic \Pol`y*syn*thet"ic\, a. [Poly- + synthetic.]
   Characterized by polysynthesis; agglutinative.

   {Polysynthetic twinning} (Min.), repeated twinning, like that
      of the triclinic feldspar, producing fine parallel bands
      in alternately reversed positions.

Source : WordNet®

polysynthetic
     adj : forming derivative or compound words by putting together
           constituents each of which expresses a single definite
           meaning [syn: {agglutinative}]