bow window

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

• noun A bay window built in a curve.

from The Century Dictionary.

• noun A window built so as to project from a wall; properly, one that is in plan a segment of a circle. See bay-window.

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

• noun architecture A curved, bow-shaped window space projecting outward from the main walls of a building, similar to a bay window.

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

• noun a window that sticks out from the outside wall of a house