Pertaining to exponents; involving variable exponents; as, an exponential expression; exponential calculus; an exponential function. Exponential curve, a curve whose nature is defined by means of an exponential equation. Exponential equation, an equation which contains an exponential quantity, or in which the unknown quantity enters as an exponent.
(Science: mathematics) exponential quantity, a quantity whose exponent is unknown or variable, as a^x. Exponential series, a series derived from the development of exponential equations or quantities.