al·lo·morph 2 
(ălə-môrf′)
(ălə-môrf′)n.
Any of the variant forms of a morpheme. For example, the phonetic (s) of cats (kăts), (z) of pigs (pĭgz), and (ĭz) horses (hôrsĭz) are allomorphs of the English plural morpheme.
[ALLO- + MORPH(EME).]
al′lo·morphic adj.
al′lo·morphism n.