(mathematical analysis) Any complex-valued measurable function whose range is finite.

(computing) A program or subroutine, provided by the user rather than being built into the system, that may return a value and may take input parameters.

(mathematics) Any function in which each point in the domain maps to just one point in the range

(mathematics) Any function whose value may be computed using a Turing machine.

(mathematics) Any function whose value is the solution of a quadratic polynomial

(mathematics) Any function, of multiple variables, whose value is independent of the order of the variables, i.e. f(a,b) = f(b,a).

(mathematics, computing) A function whose value is chosen at random from its domain / (mathematics) A function chosen at random from a set of functions

(physics) The minimum energy needed to remove an electron from the surface of a material

(probability theory) Any function whose integral over a set gives the probability that a random variable has a value in that set

(computing) Any function that uses recursion and can call itself until a certain condition is met