Hierarchy classification:

1. top of the aat hierarchies
2. Associated Concepts Facet
3. Associated Concepts (hierarchy name)
4. scientific concepts
5. mathematical concepts
6. geometric concepts
7. geometric figures
8. plane figures
9. polygons
10. quadrilaterals (polygons)

Anotations

Scope note:

In North America, "trapezoids" are quadrilateral figures having one pair of parallel and one pair of nonparallel sides. In Britain and certain other places, these figures are called a "trapeziums." "Trapezium" has a different meaning in North America, referring to figures having no parallel sides.