morphophoneme vs allomorph

morphophoneme and allomorph both are nouns.

Word	Noun	Adjective	Verb	Adverb
morphophoneme	Yes	No	No	No
allomorph	Yes	No	No	No

As nouns, allomorph is a hypernym of morphophoneme; that is, allomorph is a word with a broader meaning than morphophoneme:

morphophoneme: (linguistics) the phonemes (or strings of phonemes) that constitute the various allomorphs of a morpheme
allomorph: a variant phonological representation of a morpheme

morphophoneme (noun)	allomorph (noun)
(linguistics) the phonemes (or strings of phonemes) that constitute the various allomorphs of a morpheme	a variant phonological representation of a morpheme
	any of several different crystalline forms of the same chemical compound