Pleomorphism

The property of crystallizing under two or more distinct fundamental forms, including dimorphism and trimorphism.

The theory that the various genera of bacteria are phases or variations of growth of a number of Protean species, each of which may exhibit, according to undetermined conditions, all or some of the forms characteristic of the different genera and species.

(biology) the appearance of two or more distinctly different forms in the life cycle of some organisms

(chemistry) the existence of different kinds of crystal of the same chemical compound