pier glass

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A tall mirror, especially one placed between windows.

from The Century Dictionary.

• noun A mirror used in an apartment to cover the whole or a large part of the wall between two openings; especially, such a mirror set up between two windows, and forming a part of the decoration of a room. Compare pier-table.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tall narrow mirror, usually set between two windows, above a pier table.

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

• noun a large mirror between two windows