(mathematics) a mathematical representation of the relation between the input and output of a linear time-invariant system

(mathematics) A function, the result of the division of two exponential functions, that gives rise to the logistic curve.

(computing theory) A function from (state, input symbol) to state describing what state to move to on receiving a given input in a given state.

(mathematical analysis) Any function that is algebraically independent of its variable(s); a function which does not satisfy a polynomial equation whose coefficients are themselves polynomials.

(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