allomorph
noun
al·lo·morph ˈa-lə-ˌmȯrf 
: one of a set of forms that a morpheme may take in different contexts
the -s of cats, the -en of oxen, and the zero suffix of sheep are allomorphs of the English plural morpheme
allomorphic
ˌa-lə-ˈmȯr-fik
adjective allomorphism
ˈa-lə-ˌmȯr-ˌfi-zəm
noun 
Word History
Etymology
allo- + -morph (in morpheme), on the model of allophone : phoneme
First Known Use
1945, in the meaning defined above
Medical Definition
allomorph
noun
al·lo·morph ˈal-ə-ˌmȯrf
1
: any of two or more distinct crystalline forms of the same substance
2
: a pseudomorph that has undergone change or substitution of material