inverse function: Meaning and Definition of

in'verse func'tion

Pronunciation: [key]
— Math. Math.
  1. the function that replaces another function when the dependent and independent variables of the first function are interchanged for an appropriate set of values of the dependent variable. In y = sin x and x = arc sin y, the inverse function of sin is arc sine.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.