plate glass

from The American Heritage® Dictionary of the English Language, 4th Edition

• n. A strong rolled and polished glass containing few impurities, used for mirrors and large windows.

from Wiktionary, Creative Commons Attribution/Share-Alike License

• n. sheet glass; a type of glass, initially produced in plane form, commonly used for windows, windshields, etc.

from the GNU version of the Collaborative International Dictionary of English

• n. a fine kind of glass, cast in thick plates, and flattened by heavy rollers, -- used for mirrors and the best windows.
• n. See under Glass.

from The Century Dictionary and Cyclopedia

• n. A superior kind of thick glass used for mirrors, and also for large panes in windows, shop-fronts, etc. (See Plate, 12.)

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• n. glass formed into large thin sheets