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, "trapeziums" are quadrilateral figures having no parallel sides. In Britain and certain other places, "trapeziums" are the same as "trapezoids" in North America, that is, figures having one set of parallel lines.