Source : Webster's Revised Unabridged Dictionary (1913)

Monogamous \Mo*nog"a*mous\, a. [L. monogamus having but one
   wife, Gr. ?; ? single + ? marriage.]
   1. Upholding, or practicing, monogamy.

   2. (Bot.) Same as {Monogamian}.

   3. (Zo["o]l.) Mating with but one of the opposite sex; --
      said of birds and mammals.

Source : WordNet®

monogamous
     adj : (used of relationships and of individuals) having one mate;
           "monogamous marriage"; "monogamous for life" [ant: {polygamous}]