lexema

Lexema is a linguistic term describing the invariant core of a word that carries its core meaning and serves as the stem to which affixes attach. It is the form left when inflectional endings are removed and is the common basis for all inflected variants within a word family.

In linguistic analysis, a lexeme is the abstract lexical unit representing all the forms a word can take, typically expressed by its dictionary entry or lemma. The lexema is the stable stem shared by those inflected forms, while morphemes are the smallest units of meaning that realize affixes and derivations.

Example: the verb hablar in Spanish. The lexeme is the verb as a family (hablar, hablo, hablas, habla, hablamos, habláis, hablan). The invariant core is often described as the stem habl-, with the dictionary form hablar naming the lexeme and serving as its headword. The various endings attach to the stem to produce the different conjugated forms.

Note that definitions vary by theoretical tradition. In some grammars the lexema is the stem or root, while in others it is treated more broadly as the lemma. The distinction among lexeme, lexema, and morpheme is central to morphology, lexicography, and language learning.