In linguistics, an allomorph is a variant form of a morpheme, that is, when a unit of meaning varies in sound without changing the meaning. The term allomorph explains the comprehension of phonological variations for specific morphemes. In linguistics, an allomorph is a variant form of a morpheme, that is, when a unit of meaning varies in sound without changing the meaning. The term allomorph explains the comprehension of phonological variations for specific morphemes.