Horizontal trim board under a window stool.
Has a top-hinged sash.
Balance, or balance spring:
Device for counterbalancing a sliding sash, usually associated with a double-hung window, so sash may be held open at any given position.( See Acme Duplex for the original and still the best balances. www.AcmeDuplex.com) (link)
A window that project out from the wall and extends to ground level.
Bead (also bead stop; stop):
Wood strip against which a swinging sash closes.
Method of glazing.
Bottom horizontal part of a window sash.
Bow window (also compass, radial bay window):
A rounded bay window extending from a wall in an arc, typically built with five sashes.
Window that extends, typically for the display of goods.
Fixed oval window, often found on Colonial Revival Houses.
Window sash which either swing in or swing out on side hinges
Casing: Trim - molding or framing around a window or door.
A sash that pivots on pins in the middle of the sash stiles.
A large fixed sash with a narrow, often movable, sash on either side.
Clerestory or clearstory window
A window in the upper part of a lofty room or ceiling.
Windows with small rectangular panes, or divided lites.
Two windows that meet at a corner of a building.
Coupled window: (Double Window)
Two independent windows separated with a mullion.
Window in a wall that either projects or is recessed on a sloping roof.
A window with two sashes, each closing a different part of the window.
Fanlight, sunburst light, fan window, circle-top transom
A half-circle window over a door or window.
Fixed light or fixed sash
Window which doesn't open.
Two casement sashes hinged to open in the middle. Typically extend to the floor and servs as a door to a porch or terrace.
Window topped with a pointed arch
Hopper light, hopper vent, hopper ventilator:
Inward-opening ash hinged at the bottom.
Jalousie windows, louvered windows:
A window with overlapping narrow glass, metal, or wooden louvers, operated with a crank handle for adjusting the louver angles.
Vertical members at the side of the window frame.
Tall, narrow window with a pointed-arch top
A pane of glass within a window.
A window projecting from the wall and carried on brackets, corbels, or a cantilever. Unlike a bay window, the projection of an oriel does not extend all the way to the ground.
A form of picture window consisting of several sash or fixed glazings, separated by crossbars or mullions--or both.
Large fixed window.
Awning type window that swings either inwards or outwards at the top or the bottom.
Queen Anne window:
A window with small glass windows or lights arranged in various forms, usually only on the upper sash.
Sash (also window sash):
Framework of stiles and rails in which the lights of a window are set.
Sash and frame:
A window and its cased framing.
Side light (also Margin light):
A fixed often narrow glass window next to a door opening or window opening.
Window similar to double-hung window, except the top sash is stationary.
Window frame made from a single piece of lumber.
Window unit set at an angle in a wall.
Combined grouping of awning, hopper, casement, or non-operative windows to form a large glazed unit.
Special heat-treated, high-strength safety glass which shatters into pebble-sized particles and not in slivers.
Top hung-in window:
An awning window pivoted at the top and with the bottom swinging-in.
Transom (also transom bar):
Horizontal member separating a door from a window panel above the door, or separating one window above another.
Window sash located above a door.
Vertical sliding window:
One or more sash that move in a vertical direction.
For a complete glossary, visit the Window and Door Manufacturer’s Association