|A square is a rectangle with all four sides of equal length, as shown below.|Square of a number|The square of a number (n2) is the result of multiplying that number by itself.| Did you know? A square is also a rhombus, since it is a parallelogram in which all sides are congruent! While all squares are rhombuses, not all rhombuses are squares. This is also true regarding squares and rectangles. See also square centimeter, square unit.