from The American Heritage® Dictionary of the English Language, 4th Edition
- n. One that performs an operation or a function.
- n. Grammar See function word.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a function word
- n. a function object
- n. a structure-preserving mapping between categories: if F is a functor from category C to category D, then F maps objects of C to objects of D and morphisms of C to morphisms of D such that any morphism f:X→Y of C is mapped to a morphism F(f): F(X) → F(Y) of D, such that if then , and such that identity morphisms (and only identity morphisms) are mapped to identity morphisms. Note: the functor just described is covariant.
New Latin, from Latin fūnctiō, performance, function; see function.(American Heritage® Dictionary of the English Language, Fourth Edition)