- 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.
Origin of louver
also louvre, early 14c., "domed turret-like structure atop a building to disperse smoke and admit light," from Old French lovier, of uncertain origin. One theory connects it to Medieval Latin *lodarium, which might be from a Germanic source (cf. Old High German louba "upper room, roof;" see lobby). Another suggests it is from French l'ouvert, literally "the open place," from le, definite article, + past participle of ouvrir "to open." Meaning "overlapping strips in a window (to let in air but keep out rain)" first recorded 1550s. The form has been influenced by apparently unrelated French Louvre, the name of the palace in Paris, which is said to be so named because its builder, Philip Augustus, intended it as a wolf kennel. Related: Louvered.