A parallelogram is a quadrilateral (has four sides) in which opposite sides are parallel to each other. Also for a parallelogram, the opposite sides and angles are equal to each other.
A rhombus is a parallelogram (that is opposites sides and angles are equal to each other and parallel) with all sides of equal length. The diagonals of a rhombus bisect each other at 90° to form four equal right angled triangles with the sides of the rhombus as the hypotenuse.