In algebra, the square of x is written x2 and is defined as the product of x with itself: x × x. Taking the square is exponentiation with exponent two. If x is a positive real number, the value of x2 is equal to the area of
a (geometric) square of edge length x.
If y = x2 and x ≥ 0, then x is the square root of y.
A positive integer that is the square of some other integer is known as a square number, or more simply a square.