A window is an opening in a wall, door, roof, or vehicle that allows the exchange of light and may also allow the passage of sound and sometimes air. Modern windows are usually glazed or covered in some other transparent or translucent material, a sash set in a frame in the opening; the sash and frame are also referred to as a window.

window, opening in the wall of a building for the admission of light and air; windows are often arranged also for the purposes of architectural decoration. Since early times, the openings have been filled with stone, wooden, or iron grilles or lights (panes) of glass or other translucent material such as mica or, in the Far East, paper.