Definition:Quadrilateral/Rectangle

Definition
A rectangle is a quadrilateral all of whose angles are equal to a right angle, and whose sides may or may not all be the same length.

Also see

 * Both squares and oblongs are types of rectangle.


 * Rectangle is Parallelogram: A rectangle is a parallelogram all of whose angles are equal to a right angle.

Euclid, in, refers to this as a rectangular parallelogram.