A bow window or compass windowSturgis, Russell. "Bow window, Compass window" Sturgis' illustrated dictionary of architecture and building: an unabridged reprint of the 1901-2 edition. Mineola, N.Y.: Dover, 1989. Print. is a curved bay window."Bow window" at The Illustrated Architecture Dictionary Like bay windows, bow windows add space to a room by projecting beyond the exterior wall of a building and provide a wider view of the garden or street outside than flush windows, but combine four or more facets, differentiating them from the more common three-sided bay window.Bay Windows vs. Bow Windows: What's the Difference?, Pella Windos, pella.com Casement windows are often used for ventilation.
Bow windows first appeared in the eighteenth century in the United Kingdom (and in the Federal period in the United States).
See also Bay window Oriel window
References
External links Oriel Bow Window from Brighton & Hove Museums collection The Difference Between Bay & Bow Windows