1.AdjectiveExpressed in terms of an exponent (power of a base), the base often being 10 or e.
"In base-10 exponential form, 1,000,000 is written as 10.; If not otherwise specified, "the" exponential function is normally understood to mean e."
2.AdjectiveCharacterised 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.
"There were two deaths on Monday, four on Tuesday, and eight on Wednesday. The rate of increase seems exponential."
3.AdjectiveCharacterised by a very rapid rate of change, especially increase, or merely a very large amount or degree.
"There's been an exponential rise in the number of crimes reported this year, compared to last year."
4.NounAny function that has an exponent as an independent variable.