Definitions
1.nounA four-sided polygon with two sides parallel
2.nounA four-sided polygon with no parallel sides and no sides equal; a simple convex irregular quadrilateral.
3.nounThe trapezium bone of the wrist.
4.nounA 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.