adjective
Relating to an exponent.
(mathematics) Expressed in terms of an exponent (power of a base), the base often being 10 or e.
(mathematics) Characterised by a rate of change that is proportional to the value of the varying quantity, or, equivalently, by a doubling or halving over successive fixed intervals of time or other parameter, described as exponential growth or exponential decay.
(loosely) Characterised by a very rapid rate of change, especially increase, or merely a very large amount or degree.
noun
(mathematics) Any function that has an exponent as an independent variable.