Word Study
allomorph
CIDE DICTIONARY
allomorph, n. [Gr. other + morfh` form.].
Any one of two or more distinct crystalline forms of the same substance; or the substance having such forms; -- as, carbonate of lime occurs in the allomorphs calcite and aragonite. G. H. Williams. [1913 Webster]
OXFORD DICTIONARY
allomorph, n. Linguistics any of two or more alternative forms of a morpheme.
Derivative
allomorphic adj.
Etymology
ALLO- + MORPHEME
For further exploring for "allomorph" in Webster Dictionary Online