(mathematical analysis) Any function that is defined for all positive integers, and has values that are either real or complex.

(trigonometry) Any function of an angle expressible as the ratio of two of the sides of a right triangle that has that angle (e.g., sine), or that subtracts 1 from such a ratio or subtracts such a ratio from 1 (e.g., coversed sine).

(calculus) Of a function, another function, the value of which for any value of the independent variable is the instantaneous rate of change of the given function at that value of the independent variable.

(computing) an algorithm that generates a numeric, or fixed-size character output from a variable-sized piece of text or other data; used in database table queries, cryptography and in error-checking

(mathematics) a function of the generalized coordinates and velocities of a dynamic system from which Lagrange's equations may be derived

(physics) a mathematical function that describes the behaviour of paramagnetic materials and the dielectric properties of insulators

(mathematics) The general solution of a homogenous linear differential equation.

(programming) Programming in a style that, in lieu of assignment, uses procedure calls to bind variables to values, so that referential transparency is preserved.

Alternative spelling of wavefunction

(mathematics) Any metric space whose elements are functions