Hierarchy classification:

1. top of the aat hierarchies
2. Materials Facet
3. Materials (hierarchy name)
4. materials (substances)
5. [materials by composition]
6. inorganic material
7. glass (material)
8. [glass by technique]

Narrower term/s

• bull's eye glass

Anotations

Scope note:

Flat pane glass made by blowing a bubble of glass, transferring it from a blow-pipe to a rod, cutting it open, then rapidly rotating it until, by centrifugal force, it is spread into a flat disk. Can be either small individual panes with so-called bulls-eyes in the centers or large disks that are annealed and cut into pieces. Crown glass is thin and brilliant with a slight convexity and concentric wavy lines. Known to the ancient Romans throughout the Empire; found in windows of medieval cathedrals.