A clerestory is a row of high-level windows set above normal eye level, usually near the top of a wall or just below the roofline. Clerestory windows are used to bring daylight deeper into a building without relying on standard wall windows.

They are especially useful in barn conversions, extensions, and homes where privacy, planning constraints, or existing walls limit where new openings can be placed. In older buildings, clerestory glazing can also help introduce light while preserving the main character of the original walls.