Webster’s Revised Unabridged Dictionary · 1913
Metamerism
Me·tam′er·ism (mē·tăm′ẽr·ĭz'm), 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.