Meaning of exponential function

ex'ponen'tial func'tion

Pronunciation: [key]
— Math. Math.
  1. the function y = e.
  2. any function of the form y = ba, where a and b are positive constants.
  3. any function in which a variable appears as an exponent and may also appear as a base, as y = x
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.