- A domed structure on a roof, with side openings for ventilation
- A louver (American English) or louvre (British English), from the French l'ouvert; "the open one") is a window, blind or shutter with horizontal or, less often, vertical slats, that are angled to admit light and air, but to keep out rain, direct sunshine, and noise.
- Each of a set of angled slats or flat strips fixed or hung at regular intervals in a door, shutter, or screen to allow air or light to pass through
- (louver) one of a set of parallel slats in a door or window to admit air and reject rain
- (louvered) supplied with louvers for ventilation; "a louvered door"