Rectangle vs. Rhombus — What's the Difference?

In Euclidean plane geometry, a rectangle is a quadrilateral with four right angles. It can also be defined as: an equiangular quadrilateral, since equiangular means that all of its angles are equal (360°/4 = 90°); or a parallelogram containing a right angle.

In plane Euclidean geometry, a rhombus (plural rhombi or rhombuses) is a quadrilateral whose four sides all have the same length. Another name is equilateral quadrilateral, since equilateral means that all of its sides are equal in length.

A plane figure with four straight sides and four right angles, especially one with unequal adjacent sides, in contrast to a square.

A quadrilateral all of whose sides have the same length.

A four-sided plane figure with four right angles.

An equilateral parallelogram, especially one having oblique angles. Also called rhomb.

(geometry) Any quadrilateral having opposing sides parallel and four right angles.

(geometry) A parallelogram having all sides of equal length.

(nontechnical) Such a quadrilateral that is oblong (longer than it is wide): one that is not regular (equilateral), that is, any except a square.

The rhombus diamond, as one of the suits seen in a deck of playing cards (♦ or ♦).

A four-sided figure having only right angles; a right-angled parallelogram.

In early Greek religion, an instrument whirled on the end of a string similar to a bullroarer.

Rectangular.

Any of several flatfishes, including the brill and turbot, once considered part of the genus Rhombus, now in Scophthalmus.

A parallelogram with four right angles

Snails, now in genus Conus or family Conidae.

Same as Rhomb, 1.

A parallelogram with four equal sides; an oblique-angled equilateral parallelogram