n. (also underlying representation, underlyer) A more or less abstract phonological representation of a segment, a morpheme, a word or a phrase which is posited by an analyst and from which corresponding surface forms, including any variant...

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In phonology, the underlying representation or underlying form of a morpheme is the abstract form the morpheme is postulated to have before any phonological rules have applied to it. The underlying representation of a morpheme is considered to be...