Witch window

In American vernacular architecture, a witch window (also known as a Vermont window, among other names) is a window (usually a double-hung sash window, occasionally a single-sided casement window) placed in the gable-end wall of a house^[1] and rotated approximately 1/8 of a turn (45 degrees) from the vertical, leaving it diagonal, with its long edge parallel to the roof slope.^[1][2] This technique allows a builder to fit a full-sized window into the long, narrow wall space between two adjacent roof lines, where a window would not otherwise fit.

Witch windows are found almost exclusively in or near the U.S. state of Vermont, generally in the central and northern parts of the state.^[3] They are principally installed in farmhouses from the 19th century,^[1][2] and can be found less frequently in new construction.^[3]