According to wikopedia, The definition of a window is "... an opening in an otherwise solid, opaque surface through which light and air can pass. " By definition, this includes the early windows which didn't have any protection from the wind or rain. Early windows used shutters to protect the inside of the house from the elements. Modern windows may have be single, dual, or triple paned.



There are may different window styles, those more common today which are usually dictated by the weather conditions common to the area. Coastal climates, with stronger winds, tend to have smaller outward-opening windows while inland areas tend to have larger windows, with commonly open inwards.

* Replacement: is a framed window designed to slip inside the original window frame from the inside after the old sashes are removed

* New construction: a window with a nailing fin designed to be inserted into a rough opening from the outside before applying siding and inside trim.

Common styles are:

* Double-hung sash window: a Vertical style window with two parts (sashes) which overlap slightly and slide up and down inside the frame.

* Single-hung sash window: one sash is movable and the other fixed.

* Horizontal Sliding sash window: has two or more sashes that overlap slightly but slide horizontally within the frame. If there are 3 part, the center typically is a fixed panel.

* Casement window: An outward-opening window with either side-hung, top-hung, or combination of sash types. Often they have fixed panels on one or more sides of the sash. These are opened using a crank, by friction stays, or espagnolette locking.

* Tilt: a window which can open inwards at the top or can open hinged at the side.

* Jalousie window: A window comprising many slats of glass that open and close like a Venetian blind usually using a crank.

* Skylight: A flat, sloped, or bubble window built into a roof structure for daylighting.

* Bay: A multipanel window, with at three sections set at different angles to create an expanded area for shelving/sitting while allowing more light into the room that a flat window. The window creates a "seat board", a small seating area or shelf often used for plants or items that would take up floor space. A bay window may be rectangular, polygonal or arc shaped. If arc-shaped it is a bow window.

* Bow: a type of Bay window, but arc shaped with four or more glass sections to simulate a rounded appearance.

* Fixed: A window that cannot be opened. A non-opening window is sometimes called a "light" because its function is limited to allowing light to enter without any outside air.

* Picture: A very large fixed window in a wall, which provides an unimpeded view "as if framing a picture".

Classic styles:

* Clerestory: A fixed, vertical window set in a roof structure or high in a wall, used for daylighting. You'll see these in the old churches around the world, like Notre Dame. Clerestory lights are any rows of windows above eye level for providing light.

* Oriel: Projects from the wall, and were originally a form of a porch. Often seen on upper stories of older buildings. Often supported by brackets, or by corbels (a type of architectural bracket), they do not reach the ground. These are the rounded columnar windows you see on older buildings.

* Palladian: A large arched window which is divided into three parts. The center section is larger than the two side sections. Renaissance and classical architecture often have Palladian windows.