What is an allomorph?

Definition
	An allomorph is one of two or more complementary morphs which manifest a morpheme in its different phonological or morphological environments.

Discussion
	The allomorphs of a morpheme are derived from phonological rules and any morphophonemic rules that may apply to that morpheme.

Examples (English)
	The plural morpheme in English, usually written as '-s', has at least three allomorphs:
	[-s] as in [hQts] 'hats' [-z] as in [d&u0254;gz] 'dogs' [«z] as in [bŒks«z] 'boxes'