Definition of "lexeme"

(linguistics) A lexical item corresponding to the set of all words (or of all multi-word expressions) that are semantically related through inflection of a particular shared basic form.

1. (strictly) The abstract minimum unit of language or meaning that underlies such a set.  quotations  examples

   Quotations

   • A lexeme is a unit of lexical meaning, which exists regardless of any inflectional endings it may have or the number of words it may contain. Thus, fibrillate, rain cats and dogs, and come in are all lexemes, as are elephant, jog, cholesterol, happiness, put up with, face the music, and hundreds of thousands of other meaningful items in English.

     2003, David Crystal, The Cambridge Encyclopedia of the English Language, 2nd edition, Cambridge University Press, page 118

   • In a typical lexicalist approach (e.g. Koontz-Garboden 2006), the unmarked lexeme is taken as lexically listed, even if its meaning (as it often does) includes templatic entailments, and the derivational morphology is taken to operate on the underived form to yield the derived form. This is the case not only morphologically, but also semantically.

     2014 September 25, Rochelle Lieber, Pavol Stekauer, editors, The Oxford Handbook of Derivational Morphology‎, page 347

2. (loosely) The set itself; a lexemic family.  examples

3. (loosely) The word-form chosen to represent such a set or family.  examples

(computing) An individual instance of a continuous character sequence without spaces, used in lexical analysis (see token).  examples