dimorphism

noun

1. (countable, uncountable)The occurrence within a plant of two distinct forms of any part.
2. (countable, uncountable)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.”

3. (countable, uncountable)A property of certain substances that enables them to exist in two distinct crystalline forms.