plate glass
US /ˈpleɪt ˌɡlæs/
UK /ˈpleɪt ˌɡlæs/

1.
a type of thick, flat, and clear glass, typically used for windows, doors, and mirrors, that is manufactured by pouring molten glass onto a flat surface and then polishing it
:
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The storefront was made of large sheets of plate glass.
•
He accidentally shattered the plate glass door.