A square is a polygon with four sides of equal length and four right angles.
Because it has two pairs of parallel sides, it is a parallelogram; because all of those four sides are equal in length, it is a rhombus; because it is a parallelogram with four right angles, it is a rectangle.
In algebra, to square means to multiply a number by itself. For example, the square of 3 is 9 (3·3 = 32). (See also exponent)
(For the community space, see public square)