etymon

et·y·mon  (t-mn)

n. pl. et·y·mons or et·y·ma (-m)

1. An earlier form of a word in the same language or in an ancestor language. For example, Indo-European *duwo and Old English tw are etymons of Modern English two.

2. A word or morpheme from which compounds and derivatives are formed.

3. A foreign word from which a particular loan word is derived. For example, Latin duo, "two," is an etymon of English duodecimal.

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[Latin, from Greek etumon, true sense of a word, from neuter of etumos, true.]

Thesaurus

Noun

1.

etymon - a simple form inferred as the common basis from which related words in several languages can be derived by linguistic processes root descriptor, form, signifier, word form - the phonological or orthographic sound or appearance of a word that can be used to describe or identify something; "the inflected forms of a word can be represented by a stem and a list of inflections to be attached"