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Lexicon is also a synonym for dictionary or encyclopedic dictionary. For other uses, see lexicon (disambiguation).

In linguistics, the lexicon of a language is its vocabulary, including its words and expressions. More formally, it is a language's inventory of lexemes.

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'.

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 lexicon, lexical knowledge, or lexical concept is that person's knowledge of vocabulary.

See also

• Glossary
• Lexeme
• Lexical word
• Morphology (linguistics)
• Vocabulary

Further reading

• Aitchison, Jean. Words in the Mind: An Introduction to the Mental Lexicon. Malden, Mass.: Blackwell, 2003.