Square

A square is a quadrilateral with four equal sides and four right angles, making it both a rectangle and a rhombus. Its area equals the square of the length of one side, and its diagonals are equal in length, bisect each other at right angles, and bisect the interior angles. The square is a regular polygon, so all of its sides and angles are congruent, and it has four axes of reflective symmetry along with rotational symmetry of order four. It appears throughout geometry as the base case for area measurement, tiling and coordinate grids.