- any of a series of narrow openings framed at their longer edges with slanting, overlapping fins or slats, adjustable for admitting light and air while shutting out rain.
- a fin or slat framing such an opening.
- a ventilating turret or lantern, as on the roof of a medieval building.
- any of a system of slits formed in the hood of an automobile, the door of a metal locker, etc., used especially for ventilation.
- a door, window, or the like, having adjustable louvers.
- to make a louver in; add louvers to: to louver a door.
