higher-order function

In mathematics and computer science, higher-order functions or functionals are functions which do at least one of the following:take one or more functions as an inputoutput a function In mathematics these are also known as operators or functionals. The derivative in calculus is a common example, since it maps a function to another function.
See more at Wikipedia.org...

(HOF) A function that can take one or more functions as argument and/or return a function as its value. E.g. map in (map f l) which returns the list of results of applying function f to each of the elements of list l. See also curried function.