lexical

Lexical is an adjective used across linguistics and related fields, derived from lexicon, the stock of words in a language or a person’s vocabulary. It can refer to items of vocabulary (lexical items) as opposed to grammatical structures. In linguistics, lexical items, or lexemes, are the units of meaning that carry semantic content. Lexical semantics studies how word meaning is encoded and interpreted, including polysemy and compositionality. Lexical relations include synonyms, antonyms, hyponyms, and meronyms. Lexical fields group words by shared domain or conceptual field. Lexicalization is the process by which a concept becomes expressed in words.

In syntax, lexical choices influence combinatorial possibilities; the lexicon is contrasted with the grammar.

In computational contexts, lexical analysis is the first phase of a compiler, converting source code into tokens; in NLP, a lexicon or lexical resource is used for word-level processing, including tokenization, lemmatization, stemming, and part-of-speech tagging. Lexical ambiguity occurs when a string can be interpreted as different words or senses, as in "bat" (animal) vs. "bat" (sports equipment); disambiguation resolves that in context.

The term also appears in psycholinguistics: lexical access and lexical decision tasks measure how quickly and accurately speakers recognize real words.