Webster’s Revised Unabridged Dictionary · 1913
Dimorphous
Di·mor′phous (·fŭs), a. [Cf. F. dimorphe.] 1. (Biol.) Characterized by dimorphism; occurring under two distinct forms, not dependent on sex; dimorphic.
2. (Crystallog.) Crystallizing under two forms fundamentally different, while having the same chemical composition.