Noun
composite function (plural composite functions)
(mathematics) A function of one or more independent variables, at least one of which is itself a function of one or more other independent variables; a function of function(s).
From this perspective the chain rule therefore says: : or for short, : That is, the Jacobian of a composite function is the product of the Jacobians of the composed functions (evaluated at the appropriate points). Source: Internet
While it is always possible to directly apply the definition of the derivative to compute the derivative of a composite function, this is usually very difficult. Source: Internet