functor (plural functors)
- (grammar) a function word
- (object-oriented programming) a function object
- (category theory) A morphism between two categories which maps objects from the source category to objects of the target category and arrows from the source category to arrows of the target category, in such a way as to preserve domains and codomains (of the arrows), preserve composition, and preserve identities.
- In the category of categories, , the objects are categories and the morphisms are functors.
- (in category theory): endofunctor
grammar: function word — see function word
computing: function word — see function object
mathematics: a mapping between categories