In linguistics

Linguistics

Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

, an agent noun (or nomen agentis) is a word that is derived from another word denoting an action, and that identifies an entity that does that action

Agent (grammar)

In linguistics, a grammatical agent is the cause or initiator of an event. Agent is the name of the thematic role...

. For example, "driver" is an agent noun formed from the verb

Verb

A verb, from the Latin verbum meaning word, is a word that in syntax conveys an action , or a state of being . In the usual description of English, the basic form, with or without the particle to, is the infinitive...

 "drive". The endings "-er", "-or", and "-ist" are commonly used in English to form agent nouns. "Agent noun" is also used as the name of the derivational meaning (also called a derivateme).

Usually, derived in the above definition has the strict sense attached to it in morphology

Morphology (linguistics)

In linguistics, morphology is the identification, analysis and description, in a language, of the structure of morphemes and other linguistic units, such as words, affixes, parts of speech, intonation/stress, or implied context...

, that is the derivation

Derivation (linguistics)

In linguistics, derivation is the process of forming a new word on the basis of an existing word, e.g. happi-ness and un-happy from happy, or determination from determine...

 takes as an input a lexeme

Lexeme

A lexeme is an abstract unit of morphological analysis in linguistics, that roughly corresponds to a set of forms taken by a single word. For example, in the English language, run, runs, ran and running are forms of the same lexeme, conventionally written as RUN...

 (an abstract unit of morphological analysis) and produces a new lexeme.