As a Noun:
1. The multiplication of a number (Y) by itself a certain number of times (X) is called "Y to the power of X". For example, 2 to the power of 4 equals 16. English = power of.
Note:
1. In discussing mathematics, you make this sign between two number signs. So "2 to the power of 4" is signed "TWO POWER-OF FOUR".