Currying is the idea of interpreting an arbitrary function to be of one parameter, which returns a possibly intermediate function, which can be used further on in a calculation.

The signatures of curried functions. In the upper frame we show the signature of a function f, which takes three parameters. The frames below show the signature when f is curried. In the literature, the notation shown to the bottom right is most common. The frame to the left shows how to parse the notation (the symbol -> associates to the right).