This article is about the linguistic concept. For other uses see Lexicon (disambiguation).

In linguistics the lexicon of a language is its vocabulary including its words and expressions. A lexicon is also a synonym of the word thesaurus. More formally it is a language's inventory of lexemes. Coined in English 1603 the word "lexicon" derives from the Greek "" (lexicon) neut. of "" (lexikos) "of or for words"1 from "" (lexis) "speech" "word"2 and that from "" (lego) "to say" "to speak".3

The lexicon includes the lexemes used to actualize words. Lexemes are formed according to morpho-syntactic rules and express sememes. In this sense a lexicon organizes the mental vocabulary in a speaker's mind: First it organizes the vocabulary of a language according to certain principles (for instance all verbs of motion may be linked in a lexical network) and second it contains a generative device producing (new) simple and complex words according to certain lexical rules. For example the suffix '-able' can be added to transitive verbs only so that we get 'read-able' but not 'cry-able'.

Usually a lexicon is a container for words belonging to the same language. Some exceptions may be encountered for languages that are variants like for instance Brazilian Portuguese compared to European Portuguese where a lot of words are common and where the differences may be marked word by word.

When linguists study the lexicon they study such things as what words are how the vocabulary in a language is structured how people use and store words how they learn words the history and evolution of words (i.e. etymology) types of relationships between words as well as how words were created.

An individual's mental lexicon lexical knowledge or lexical concept is that person's knowledge of vocabulary. The role the mental lexicon plays in speech perception and production as well as questions of how words from the lexicon are accessed is a major topic in the fields of psycholinguistics and neurolinguistics where models such as the cohort model have been proposed to explain how words in the lexicon are retrieved. See also Glossary Lexical markup framework Function word Morphology (linguistics) Lexicography Lexicology Idiolect Further reading Aitchison Jean. Words in the Mind: An Introduction to the Mental Lexicon. Malden MA: Blackwell 2003. Zuckermann Ghil'ad (2003). Language Contact and Lexical Enrichment in Israeli Hebrew. Palgrave Macmillan. ISBN 140391723X.  References Look up lexicon in Wiktionary the free dictionary. Henry George Liddell Robert Scott A Greek-English Lexicon on Perseus Digital Library Henry George Liddell Robert Scott A Greek-English Lexicon on Perseus Digital Library Henry George Liddell Robert Scott An Intermediate Greek-English Lexicon on Perseus Digital Library

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