According to the Oxford English Dictionary, to expone is to "set forth", and an exponent is a person or a statement that sets something forth. The word has assumed a plethora of other meanings:

Exponentiation is a mathematical operation, written an, involving two numbers, the base a and the exponent n. When n is a positive integer, exponentiation corresponds to repeated...

Exponential function

Exponential growth

Exponential family

Exponential distribution

Matrix exponential

Exponential decay

Purdue Exponent

The Exponents

Exponent (group theory)

List of exponential topics (Mathematics-related exponents)

Exponential (record label)

Exponential (disambiguation)