dimorphism

noun3

1. •
   The occurrence within a plant of two distinct forms of any part.
2. •
   The occurrence in an animal species of two distinct types of individual.

   • This is also done for Dizygopleura landesi Roth and Eukloedenella pontotocensis Lundin, new species, which illustrate domiciliar (kloedenellid) dimorphism. — 1965
3. •
   A property of certain substances that enables them to exist in two distinct crystalline forms.