Aperture in a wall to allow light and air to enter a building. If a window-aperture is divided into compartments by means of, say, mullions and transoms, those compartments are lights. In its simplest form, a window is a mere hole in a wall, with an arch or lintel at its head. Some Greek windows on important buildings were narrower at the top than at the bottom (see Tivoli and Vitruvian opening), and had architraves, often with crossettes , as in the Philippeion at Olympia (begun 339 BC).
oman windows were much larger and more varied in type especially after glazing was readily available by c. AD 65, although other materials were in use until the early C18. Thin parchment stretched on a frame, then painted and varnished; parchment painted and coated with linseed-oil; linen painted and coated with white of egg and gum-water and varnished; paper soaked in poppy-oil, mutton suet, or wax; and linen dipped or coated in beeswax were employed. In many cases glazing was found only in the upper part of the window, the lower part having wooden shutters, and this arrangement was commonly found even in Scotland’s Royal palaces until comparatively recently (C18). In Classical architecture, windows not only had architraves, but were crowned with entablatures with or without pediments. In grander window-openings, columns or pilasters may be found on either side supporting an entablature, gable, pediment, etc., in which case they are said to be aediculated. Read more