poly·morph I. \ˈpälēˌmȯrf, -lə̇ˌm-\noun (-s) Etymology: International Scientific Vocabulary, from polymorphous 1.: a polymorphous organism; also: one of several forms of such an organism 2.: any of the crystalline forms of a polymorphous substance 3.: a polymorphonuclear leukocyte II. adjective : polymorphic