Definition - Pertaining to the vocabulary (i.e. the words) of a language.

1. As opposed to the grammatical, which pertains to the structure and the rules of a language.

Etymology -
The word derives from the Greek lexikos, pertaining to words (from lexis, word).

Oxford English Dictionary -
Its first citation is from 1836:
"These methods may be respectively called, lexical and grammatical comparison."
(Card. Wiseman Sci. & Relig. I. ii. 71)

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