Definition:Quadrilateral/Trapezoid

Definition
A trapezoid is a quadrilateral which has exactly one pair of sides parallel:


 * Trapezoids.png

Thus, by this definition, a parallelogram is not a trapezoid.

Also defined as
Outside the US (one of a few countries that use this definition), a trapezoid is a quadrilateral with no parallel sides, that is, what the US defines as a trapezium.

Also known as
Outside the US (one of a few countries that use this definition), this figure is known as a trapezium.

, in his definitions, did not distinguish between trapezia and trapezoids.