Question

a rhombus is a square

Answer 1

In geometry, a rhombus is a quadrilateral in which all of the sides are of equal length, i.e., it is an equilateral quadrangle. If any angle of an equilateral quadrangle is a right angle, then all its angles are right angles and it is also a square. In colloquial usage the shape is often described as a diamond or lozenge.