Meaning of hyperbolic function

hy'perbol'ic func'tion

Pronunciation: [key]
— Math. Math.
  1. a function of an angle expressed as a relationship between the distances from a point on a hyperbola to the origin and to the coordinate axes, as hyperbolic sine or hyperbolic cosine: often expressed as combinations of exponential functions.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.