A rhombus is a parallelogram with four sides of the same length.

Because the rhombus is a parallelogram, it has all the properties of a parallelogram.
In a rhombus, there are:
(1) two pairs of parallel sides,
(2) four sides that are all congruent to each other,
(3) diagonals that bisect the angles, and
(4) diagonals that are perpendicular bisectors of each other.