A rhombus is a two-dimensional shape and is also characterized as a special parallelogram. It has four equal sides, with the opposite angles being equal to each other, whereas its adjacent angles are supplementary.
A rectangle is a also two-dimensional shape. It has four equal angles and four vertices. All the four angles of a rectangle measure 90°.
Rhombuses and Rectangles have the following differences:
1) A rhombus has four equal sides while in a rectangle, the opposite sides are equal.
2) The diagonals of a rhombus bisect each other at 90° while the diagonals of a rectangle bisect each other at different angles.