Bow window
A bow window or compass window is a curved bay window. 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. Casement windows are often used for ventilation.
Bow windows first appeared in the eighteenth century in the United Kingdom.