Page "Square root" Paragraph 2

Every non-negative real number a has a unique non-negative square root, called the principal square root, which is denoted by, where √ is called the radical sign or radix.

For example, the principal square root of 9 is 3, denoted, because and 3 is non-negative.

The term whose root is being considered is known as the radicand.

The radicand is the number or expression underneath the radical sign, in this example 9.