Source : Webster's Revised Unabridged Dictionary (1913)

Metamerism \Me*tam"er*ism\, n.
   1. (Biol.) The symmetry of a metameric structure; serial
      symmetry; the state of being made up of metameres.

   2. (Chem.) The state or quality of being metameric; also, the
      relation or condition of metameric compounds.