“Bull’s eye” — a glass pane with a pontil mark surrounded by concentric ridges. This was the central part of a large pane of crown glass. In the 19th century used as a decorative element.
Hot glass painting — painting with schwarzlot, enamel, grisaille and other materials followed by firing.
Stained glass — the term refers to window décor meant primarily for religious and sometimes secular architecture. This glass art is made in a special technique that includes binding together coloured and painted fragments of glass.