what do you call a sheet of glass
Architectural glass This method for manufacturing flat glass panels was very expensive and could not be used to make large panes. It was replaced in the 19th century by the cylinder, sheet, and rolled plate processes, but it is still used in traditional construction and restoration.
Glass ceiling The first person to use the phrase was Marilyn Loden, during a 1978 speech.[15][16] The concept of the glass ceiling was later popularized at the National Press Club in July 1979.[citation needed] This was at a Conference of the Women's Institute for Freedom of the Press led by Katherine Lawrence of Hewlett-Packard. This was part of an ongoing discussion of a clash between written policy of promotion versus action opportunities for women at HP.