Double-Hung—Top and bottom sash slide up and down within the window frame. With most current window models, the sash not only vertically, but tilt in for cleaning. Single-hung windows look similar, but only the lower sash moves up and down. Other variations of hung windows include cottage windows, which feature a bottom sash that is greater in height than the upper sash. Triple-hung windows, with three sliding sash, are also used in some very large openings
Bay and Bow
Bay—Windows that protrude from the exterior wall and consist of a center fixed or picture window and two operable flanking units on either side,
angled back toward the main wall.
Bow—Like bays, bow windows also protrude from the exterior wall. They generally consist of a series of narrow casement or fixed windows combined in a gently-formed arc. An oriel is an older term for a bay or bow window unit that is supported at the bottom by brackets or corbels
Awning—Similar to casements, except the sash is hinged to the top of the window frame. Opening out in this manner
Horizontal Slider—Sash slide horizontally within the frame.
Also called sliding windows or gliders, these units may feature one fixed (non-moving) sash and usually one or two sliding sash.
Garden—These windows, generally designed to provide a location to grow plants, protrude from a wall and generally feature a fixed window in the middle with two operable flanking units, typically at a 90° angle to the wall. The top of the window features sloped or curved glass to maximize exposure of sunlight on plants.
Casement—The sash of casement windows are hinged on the side of the window frame and swing out left or right. Most are operated by a crank. Models that don’t use a crank are commonly referred to as push-out casements. A French casement features two push-out sash that are hinged on opposite sides of the same frame.