Higher-order function

In mathematics and computer science, higher-order functions are functions which can take other functions as arguments, and may also return functions as results. The derivative in calculus is a common example of a higher-order function, since it maps a function to another function. Higher-order functions were studied long before the notion of functional programming existed, in the lambda calculus, a formalism which has influenced the design of several functional programming languages, especially the Haskell programming language.