Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Components (hierarchy name)
4. components (objects parts)
5. [components by specific context]
6. architectural elements
7. [openings and opening components]
8. openings (architectural elements)
9. [openings by form]
10. [windows and window components]
11. window components
12. [window frames and window frame components]
13. window frame components
14. window sills

Anotations

Scope note:

Window sills that consist of a stone slab as long as the window is wide and that fit into the walls between the jambs; distinguished from "lug sills" which are longer than the width of the window opening and are let into the wall on each side.