Lexeme

For its use in the context of computer science, seeLexeme (computer science).

Alexeme(/ˈlɛksiːm/) is a unit oflexicalmeaning that underlies a set of words that are related throughinflection.It is a basic abstract unit of meaning,aunitofmorphologicalanalysisinlinguisticsthat roughly corresponds to a set of forms taken by a single rootword.For example, inEnglish,run,runs,ranandrunningare forms of the same lexeme, which can be represented asRUN.

One form, thelemma(or citation form), is chosen by convention as the canonical form of a lexeme. The lemma is the form used in dictionaries as an entry'sheadword.Other forms of a lexeme are often listed later in the entry if they are uncommon or irregularly inflected.

Description

The notion of the lexeme is central tomorphology,the basis for defining other concepts in that field. For example, the difference betweeninflectionandderivationcan be stated in terms of lexemes:

• Inflectional rules relate a lexeme to its forms.
• Derivational rules relate a lexeme to another lexeme.

A lexeme belongs to a particularsyntactic category,has a certainmeaning(semantic value), and in inflecting languages, has a correspondinginflectional paradigm.That is, a lexeme in many languages will have many different forms. For example, the lexemeRUNhas a presentthird personsingularformruns,a present non-third-person singular formrun(which also functions as thepast participleandnon-finiteform), a past formran,and a presentparticiplerunning.(It does not includerunner, runners, runnableetc.) The use of the forms of a lexeme is governed by rules ofgrammar.In the case of English verbs such asRUN,they include subject–verbagreement and compoundtenserules, which determine the form of a verb that can be used in a givensentence.

In manyformaltheories oflanguage,lexemes havesubcategorization framesto account for the number and types of complements. They occur withinsentencesand othersyntactic structures.

Decomposition

A language's lexemes are often composed of smaller units with individual meaning calledmorphemes,according toroot morpheme+derivational morphemes+affix(not necessarily in that order), where:

• The root morpheme is the primary lexical unit of a word, which carries the most significant aspects of semantic content and cannot be reduced to smaller constituents.
• The derivational morphemes carry onlyderivationalinformation.
• Theaffixis composed of all inflectional morphemes, and carries onlyinflectionalinformation.

The compound root morpheme + derivational morphemes is often called thestem.The decomposition stem +desinencecan then be used to study inflection.

See also

• Ending (linguistics)
• Inflection
• Lemma
• Lexical word vs. grammatical word
• Marker (linguistics)
• Multiword expression
• Null morpheme
• Root (linguistics)
• Stem
• Syntagma (linguistics)
• Word family

External links

• The dictionary definition oflexemeat Wiktionary