Main Page | See live article | Alphabetical index One might be looking for window (computing) or X Window System. Double-hung sash window Table of contents 1 Opening in wall 1.1 Windows styles 1.2 Meaning of "window" 2 See also 3 Astronomical window 4 World War II Opening in wall A window is an opening in the wall of a building that allows light to enter a room and people to see out. At previous times in history they were merely small oval or square holes in the walls. Very early windows were shielded with hide or cloth stretched over the opening or wooden shutters. Later on two different types of windows were invented: mullioned glass windows, which multiple very small pieces of glass joined together with leading, and paper windows. Mullioned glass windows were the windows of choice among European riches, whereas paper windows were so economical and widely used in ancient China and Japan. In England glass only became common in the windows of ordinary homes in the early 17th century. Modern-style floor-to-ceiling windows only became possible after the industrial glass-making process was perfected. Modern windows are customarily large glassed-in rectangles or squares. Churches traditionally have stained glass windows. Today a window can be made in any shape and size desired. Windows styles Modern windows come in many styles. These include: Double-hung sash window: the traditional style of window, with two separate pieces which overlap slightly and which slide up and down inside a frame; each movable piece is termed a sash Sliding window: with two or more separate pieces that overlap slightly, at least one of which slides sideways within a frame Casement window: a window which turns out at an angle, staying fixed along one side, usually opening by a cranked mechanism Jalousie window: a window (or door) comprising many slats of glass, which open and close like a Venetian blind, usually by a cranked mechanism Clerestory window: a vertical window set in a roof structure or high in a wall, used for daylighting Skylight: a flat or sloped window built into a roof structure for daylighting Bay window: a multi-panel window, with at least three panels set at different angles to create a protrusion from the wall line Picture window: a very large window in a wall, intended to provide an unimpeded view Fixed window: a window which cannot be opened The terms "single-light" or "double-light" (or "'more'-light") refer to the number of glass panes in a window. Meaning of "window" The word Window dates back to Old Norse "Wind Eye"; opening to the air. The beam or arch over the top of a window is known as the lintel or transom. See also The window cleaner Windex® Astronomical window In astronomy, an atmosphere can have a window for portions of the electromagnetic spectrum; that is, those wavelengths which pass through the atmosphere are said to "pass through a window." World War II Window was the WWII UK codename for a system intended to confuse German radar. It consisted of huge volumes of aluminium foil strips cut to a length corresponding to the radar wavelength which were dropped from aircraft so producing huge numbers of spurious echoes. A modern corresponding technique is "chaff". Other radar confusing techniques included Mandrel, Piperack and Jostle. This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.