A "square" (2nd power) is the result of multiplying a number by itself. For example, the square of 3 is 9 because 3 x 3 = 9.

A "square root" (-2 power) is in the opposite exponential direction: you are finding the number which multiplied by itself will equal your given number. Using the same example, the square root of 9 is 3, because 3 x 3 = 9.

Except for numbers that are squares of integers, most square roots will be long non-repeating decimals. (The square root of 2 is 1.414213562...)