Standard Lemma guide

functor

noun · 4 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

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  • Received-Pronunciation: /ˈfʌŋktə/
  • US: Recorded audio is listed in the source snapshot.

1

noun

Meaning 1

A function word.

Definition source: English Wiktionary via Wiktextract

Topics: grammar, human-sciences, linguistics, sciences

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

2

noun

Meaning 2

A function object.

Definition source: English Wiktionary via Wiktextract

Qualifier: object-oriented programming

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

noun

Meaning 3

A category homomorphism; a morphism from a source category to a target category which maps objects to objects and arrows to arrows (either covariantly or contravariantly), in such a way as to preserve morphism composition and identities.

Definition source: English Wiktionary via Wiktextract

Topics: category-theory, computing, engineering, mathematics, natural-sciences, physical-sciences, sciences

Examples

  • In the category of categories #92;mathbf#123;Cat#125; the objects are categories and the morphisms are functors.
  • 1991, Natalie Wadhwa (translator), Yu. A. Brudnyǐ, N. Ya. Krugljak, Interpolation Functors and Interpolation Spaces, Volume I, Elsevier (North-Holland), page 143, Choosing for U the operation of closure, regularization or relative completion, we obtain from a given functor F∈JF the functors ◌̅F: overrightarrow X→◌̅F( overrightarrow X),F0: overrightarrow X→F( overrightarrow X)0,Fc: overrightarrow X→F( overrightarrow X)c.
  • 2009, Benoit Fresse, Modules Over Operads and Functors, Springer, Lecture Notes in Mathematics: 1967, page 35, In this chapter, we recall the definition of the category of Σ_*-objects and we review the relationship between Σ_*-objects and functors. In short, a Σ_*-object (in English words, a symmetric sequence of objects, or simply a symmetric object) is the coefficient sequence of a generalized symmetric functor S(M):X→S(M,X), defined by a formula of the form S(M,X)=⨁ ᪲r=0(M(r)⊗X)_(Σr).

Meaning relationships

Synonyms: none provided

Antonyms: none provided

Broader terms: morphism

4

noun

Meaning 4

A structure allowing a function to apply within a generic type, in a way that is conceptually similar to a functor in category theory.

Definition source: English Wiktionary via Wiktextract

Qualifier: functional programming

No example sentence was provided for this meaning.

Meaning relationships

Synonyms: none provided

Antonyms: none provided

History

Etymology

From function, modeled after factor.

Across languages

Translations

23 source translations are retained for this English entry.

  • Finnish: funktio-olio — object-oriented programming: function object
  • French: foncteur — object-oriented programming: function object
  • Polish: funktor — object-oriented programming: function object
  • Bashkir: функтор (funktor) — category theory: category mapping
  • Chinese Mandarin: 函子 (hánzǐ) — category theory: category mapping
  • Finnish: funktori — category theory: category mapping
  • Finnish: ylinuoli — category theory: category mapping
  • French: foncteur — category theory: category mapping
  • German: Funktor — category theory: category mapping
  • Hungarian: funktor — category theory: category mapping
  • Icelandic: varpi — category theory: category mapping
  • Irish: feidhmeoir — category theory: category mapping
  • Italian: funtore — category theory: category mapping
  • Japanese: 関手 (kanshu) — category theory: category mapping
  • Kazakh: функтор (funktor) — category theory: category mapping
  • Kyrgyz: функтор (funktor) — category theory: category mapping
  • Polish: funktor — category theory: category mapping
  • Portuguese: functor — category theory: category mapping
  • Portuguese: funtor — category theory: category mapping
  • Russian: функтор (funktor) — category theory: category mapping
  • Spanish: funtor — category theory: category mapping
  • Spanish: functor — category theory: category mapping
  • Swedish: funktor — category theory: category mapping
Real reading context

functor in complete knowledge articles