pleomorphism
Ple`o*mor"phism, n. Etym: [Gr. 1. (Crystallog.) Defn: The property of crystallizing under two or more distinct fundamental forms, including dimorphism and trimorphism. 2. (Biol.) Defn: 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.