rectangle -
a parallelogram with four right angles
parallelogram a quadrilateral whose opposite sides are both parallel and equal in length
foursquare,
square a hand tool consisting of two straight arms at right angles; used to construct or test right angles; "the carpenter who built this room must have lost his square"
A rectangle is any quadrilateral with four right angles. The term "oblong" is occasionally used to refer to a non-square rectangle. A rectangle with vertices ABCD would be denoted as ABCD.
OmegaWiki Dictionary
Ω
rectangle A plane figure with 4 sides and 4 right angles.