window
An opening in the wall of a building for the admission of light, and of air when necessary. This opening has a frame on the sides, in which are set movable sashes, containing panes of glass. In the United Sates, the sashes are made to rise and fall, for the admission or exclusion of air. In France, windows are shut with frames or sashes that open and shut vertically, like the leaves of a folding door.