Allomorph

The variants of morpheme are called allomorphs. Morphemes are abstract, what actually occurs, or what we hear is morphes. One morpheme can be realized by more than one morph. The morphes which belong to one morpheme are called allomorphs of the morpheme. Plural morpheme in English, for example, has allomorphs [s], [z], and [ez]. If we symbolyze the morpheme plural as {s}, we can say that the allomorphs of the morpheme {s} are [s], [z], and [ez]