Meaning

adjective relating to the crystallization of a compound in two or more different forms

adjective relating to the occurrence of more than one kind of individual (independent of sexual differences) in an interbreeding population

adjective having or occurring in several distinct forms

originFrom New Latin polymorphus, from Ancient Greek πολύμορφος (polúmorphos, “multiform, manifold”), from πολυ- (polu-, “many, much”) + μορφή (morphḗ, “form, shape”). By surface analysis, poly- + -morphous.

Etymology from Wiktionary, CC BY-SA 3.0