Rhomboid

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It has been suggested that this article be merged into Parallelogram. (Discuss) Proposed since March 2025.

Rhomboid
A rhomboid is a parallelogram with two edge lengths and no right angles
Type	quadrilateral, trapezium
Edges and vertices	4
Symmetry group	C2, [2]+,
Area	b × h (base × height); ab sin θ (product of adjacent sides and sine of the vertex angle determined by them)
Properties	convex

Traditionally, in two-dimensional geometry, a rhomboid is a parallelogram in which adjacent sides are of unequal lengths and angles are non-right angled.

The terms "rhomboid" and "parallelogram" are often erroneously conflated with each other (i.e, when most people refer to a "parallelogram" they almost always mean a rhomboid, a specific subtype of parallelogram); however, while all rhomboids are parallelograms, not all parallelograms are rhomboids.

A parallelogram with sides of equal length (equilateral) is called a rhombus but not a rhomboid. A parallelogram with right angled corners is a rectangle but not a rhomboid. A parallelogram is a rhomboid if it is neither a rhombus nor a rectangle.