LEXIS. A term in especially British LINGUISTICS for the VOCABULARY of a language or sub-language, consisting especially of its stock of LEXEMES. The term became popular because it is unambiguous, unlike LEXICON, and is GREEK in origin (fitting well with such other terms of Greek origin as phonology and syntax), in contrast with Latin-derived vocabulary (associated with Latinate pronunciation and Greco-Latin grammar).

lex·is / ˈleksis/ • n. the total stock of words in a language: a notable loss of English lexis. ∎  the level of language consisting of vocabulary, as opposed to grammar or syntax.