(management) Any primary business function that would affect customers or profits if interrupted

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

(physics) A function which describes the intensity of scattered radiation in any given direction

(mathematics) an inverse trigonometric function

An electronic analog computing device that accepts as input two periodic functions and outputs their mathematical product

(mathematics) Any function that is composed of algebraic functions, trigonometric functions, exponential functions and/or logarithmic functions, combined using addition, subtraction, multiplication and/or division

(computing) Any of a set of keys on a personal computer or terminal keyboard used to activate a predefined or programmable function.

(mathematics) A function of two, three or n variables which is a solution to any of Laplace's equations

(mathematics) Any of a set of functions the value of which can not be deduced from that of all the others.

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