principal root	The positive square root of a number, as in . By definition, the radical symbol always means to find the principal root. Note that zero has only one square root, itself (since 0 • 0 = 0).
product raised to a power rule	The product of two or more non-zero numbers raised to a power equals the product of each number raised to the same power: (ab)^x= a^x • b^x
radical symbol	The symbol, , used to denote the process of taking a root of a quantity.
radicand	The number or value under the radical symbol.
square root	A number that when multiplied by itself gives the original nonnegative number. For example, 6 • 6 = 36 and −6 • −6 = 36 so 6 is the positive square of 36 and −6 is the negative square root of 36.