Source : Webster's Revised Unabridged Dictionary (1913)

Polygamous \Po*lyg"a*mous\, a. [Gr. ? living ? polygamy; poly`s
   many + ? marriage. Cf. {Bigamy}.]
   1. Of or pertaining to polygamy; characterized by, or
      involving, polygamy; having a plurality of wives; as,
      polygamous marriages; -- opposed to {monogamous}.

   2. (Zo["o]l.) Pairing with more than one female.

            Most deer, cattle, and sheep are polygamous.
                                                  --Darwin.

   3. (Bot.) Belonging to the Polygamia; bearing both
      hermaphrodite and unisexual flowers on the same plant.

Source : WordNet®

polygamous
     adj 1: having more than one mate at a time; used of relationships
            and individuals [ant: {monogamous}]
     2: having several forms of gametoecia on the same plant [syn: {heteroicous},
         {polyoicous}]