Definition - (Aka lexical unit | lexical item)

A set of words that has the same base form.

For example, run, runs, ran and running are all members of the same lexeme; the base form is run.

Etymology -
The word derives from the Greek lexis, word (from legein, speak).

Oxford English Dictionary -
Its first citation is from 1940:
"C. F. Voegelin has accomplished the difficult and signal work of analyzing an immense number of baffling stem compounds of Shawnee into their component lexemes (stems) and other morphemes (formatives)."
(B. L. Whorf Lang., Thought, & Reality (1956) 160)

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