Allomorph

n.

1.

(Min.) 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.

Noun	1.	allomorph - any of several different crystalline forms of the same chemical compound; "calcium carbonate occurs in the allomorphs calcite and aragonite"
	2.	allomorph - a variant phonological representation of a morpheme; "the final sounds of `bets' and `beds' and `horses' and `oxen' are allomorphs of the English plural morpheme"

chemical compound, compound