\Ple`o*mor"phism\, n. [Gr. ? more + ? form.]
1. (Crystallog.) The property of crystallizing under two or
   more distinct fundamental forms, including dimorphism and
   trimorphism.
2. (Biol.) 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.