A function of one variable that is related to a function of several variables. Let f be a function of two variables, x and y. Then by considering x constant we obtain a function in y; this function depends on the value of x. We write
g(x)(y) = f(x,y)
where g is called a curried version of f. Note that g(x) denotes a function rather than a plain value. Currying is often used in theoretical work to deal simply with functions of several variables, e.g. in the lambda calculus.