A

David

Darling

codomain

A function f from X to Y. The blue oval Y is the codomain of f. The yellow oval inside Y is the image of f.

A function f from X to Y. The blue oval Y is the codomain of f. The yellow oval inside Y is the image of f.


The codomain, for a given function or mapping, is a set within which the values of the function lie. This is different from the set of values, known as the range, that the function actually takes.