(organic chemistry) A specific grouping of elements that is characteristic of a class of compounds, and determines some properties and reactions of that class.

(mathematics) A function which, when applied a given number of times, equals another given function.

(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) A meromorphic function which generalizes the notion of factorial to complex numbers and has singularities at the nonpositive integers; any of certain generalizations or analogues of said function, such as extend the factorial to domains other than the complex numbers.

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

(mathematics) A set functions that are analogues of the trigonometric functions for hyperbolic spaces. They can be derived from some arithmetic operations on the exponential function with base e and the inverse function, and was named after the corresponding similar trigonometric function.

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

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