Alexeme (/ˈlɛksiːm/ⓘ) is a unit oflexical meaning that underlies a set of words that are related throughinflection. It is a basic abstract unit of meaning,[1] aunit ofmorphologicalanalysis inlinguistics that roughly corresponds to a set of forms taken by a single rootword. For example, inthe English language,run,runs,ran andrunning are forms of the same lexeme, which can be represented asRUN.[note 1]
One form, thelemma (or citation form), is chosen by convention as thecanonical 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.
The notion of the lexeme is central tomorphology,[2] the basis for defining other concepts in that field. For example, the difference betweeninflection andderivation can 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 lexemeRUN has a presentthird personsingular formruns, a present non-third-person singular formrun (which also functions as thepast participle andnon-finite form), a past formran, and a presentparticiplerunning. (It does not includerunner, runners, runnable etc.) The use of the forms of a lexeme is governed by rules ofgrammar. In the case of English verbs such asRUN, they include subject–verb agreement and compoundtense rules, which determine the form of a verb that can be used in a givensentence.
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.[3]
The derivational morphemes carry onlyderivational information.[4]
Theaffix is composed of all inflectional morphemes, and carries onlyinflectional information.[5]
The compound root morpheme + derivational morphemes is often called thestem.[6] The decomposition stem +desinence can then be used to study inflection.
^RUN is here intended to display insmall caps. Software limitations may result in its display either in full-sized capitals (RUN) or in full-sized capitals of a smaller font. Either is regarded as an acceptable substitute for genuine small caps.
