base

The expression that is being raised to a power when using exponential notation. In 53, 5 is the base, which is the number that is repeatedly multiplied. 53 = 5 • 5 • 5. In ab, a is the base.

exponent

When a number is expressed in the form ab, b is the exponent. The exponent indicates how many times the base is used as a factor. Power and exponent mean the same thing.

exponential decay

An exponential function of the form f(x) = bx, where 0 < b < 1. The function decreases as x increases.

exponential function

A function of the form f(x) = bx, where b > 0 and b ≠ 1.

exponential growth

An exponential function of the form f(x) = bx, where b > 1, and b ≠ 1. The function increases as x increases.

half-lifeThe amount of time it takes a substance to decrease to half its original amount.
principalIn finance, the amount of money on which interest is calculated.