
Trapezoid
In Euclidean geometry, a convex quadrilateral with at least one pair of parallel sides is referred to as a trapezoid () in American and Canadian English but as a trapezium () in English outside North America. The parallel sides are called the bases of the trapezoid and the other two sides are called the legs or the lateral sides (if they are not parallel; otherwise there are two pairs of bases). A scalene trapezoid is a trapezoid with no sides of equal measure, in contrast to the special cases below.

Trapezoid (noun)
A (convex) quadrilateral with two (nonadjacent) parallel sides.

Trapezoid (noun)
A convex quadrilateral with no sides parallel and no equal sides.

Trapezoid (noun)
The trapezoid bone of the wrist.

Trapezium (noun)
A foursided polygon with two sides parallel

Trapezium (noun)
A foursided polygon with no parallel sides and no sides equal; a simple convex irregular quadrilateral.

Trapezium (noun)
The trapezium bone of the wrist.

Trapezium (noun)
A region on the ventral side of the brain, either just back of the pons Varolii, or, as in man, covered by the posterior extension of its transverse fibers.