Palladian window:
A large, arch-top window flanked by smaller windows on each side.
Panel:
Usually refers to the glazed panel or panels in a door frame.
Parting slip:
A thin wood strip separating the sash weights in the weight box of each jamb of old double-hung windows.
Parting stop:
A vertical strip on each jamb that separates the sash of a double-hung window.
Picture window:
Large fixed windows.
Pivot window units:
Window units in which the sash hardware is located near the midpoint of the stile or rail to permit sash rotation.
Prime sash:
Balanced or moving sash of a window unit.
Prime window:
Window with single or multiple glazing. A storm sash may be installed.
Projected window:
Awning type window that swings either inwards or outwards at the top or the bottom. The window usually may be cleaned from the inside.
Quarrel:
A diamond- or square-shaped glass piece set diagonally. A medieval term for small panes of glass set diagonally in Gothic windows.
Queen Anne window:
A window with small glass windows or lights arranged in various forms, usually only on the upper sash. Appeared l870s.
Rail:
Horizontal member of a window sash or door panel.
Reglet:
Plastic or wood molding put in a concrete or masonry opening for a uniform groove for a spline-type gasket to hold window glass.
Reversible extension blind stop:
An extension blind stop that is rabbetted to receive l/2 or 25/32-in. sheathing.
Rough Opening:
A framed opening in which the unit will be installed.
R-Value:
The measurement of resistance to heat transfer in a material. The higher the R-Value, the greater the insulation value.
Sash:
Framework of stiles and rails in which the glass of a window or door is set.
Saddle bar:
Light steel bar placed horizontally across a window to stiffen leaded glazing.
Saddle bead:
Glazing bead for securing two panes.
Sash lock:
A lock applied to the window to pull the sash tightly against the frame (casement) or to pull the check rails together (double-hung) in order to seal the sash from weather and for security.
Single-hung window:
Window similar to double-hung window, except the top sash is stationary.
Seat board:
A flat board cut to fit the contour of a bow or bay window and installed between the sill and the wall surface, providing a seat or a shelf space for plants, etc.
Shading coefficient:
Decimal value which is the solar gain of a window, divided by the solar gain for a clear single-glass
window of the same size. The shading coefficient of clear, double-glazing is about 0.85 to 0.9.
Side light: A fixed, often narrow glass window next to a door opening or window opening.
Sill: Horizontal member at the bottom of the window frame.
Simulated divided lights: A method in constructing windows or doors in which muntins are fixed to the inside and outside of the insulated glass panel to simulate the look of a true divided light. Modern Divided Light® in EAGLE terminology.
Single glazing: Use of single panes of glass in a window sash or door panel. Not as efficient as double glazing.
Single-hung window: Window similar to double-hung window, except the top sash is stationary.
Slide-by window: Windows which slide horizontally.
Smartwindow: Generic term that refers to windows with switchable coatings to control solar gain.
Solid frame: Window frame made from a single piece of lumber.
Sound-insulating glass (also sound-resistive glass): Double glass fixed on resilient mountings and separated so as to reduce sound transmission.
Splayed window: Window unit set at an angle in a wall.
Stacked windows: Combined grouping of awning, casement, or non-operative windows to form a large glazed unit.
Stile: Vertical member of a window sash or door panel.
Stile Lug or Horn: One of two extensions of the sash stiles to support the upper sash of a double-hung window.
Storm clip: Device attached to the muntin of a metal sash to stop the pane from moving outwards.
Stool: An interior trim on a window which extends the sill and acts as a narrow shelf. Often seen on double-hung window.
Stop: A wood trim member nailed to a window frame to hold, position or separate window parts.
Tandem lock: A locking system which secures the window at two locking points by the operation of one lever.
Tempered glass: Special heat-treated, high-strength safety glass which shatters into pebble-sized particles and not in slivers.
Tenon: A rectangular projection cut out of a piece of wood for insertion into a mortise.
Thermal break: A thermal insulating barrier between two thermally conductive materials.
Transom joint: Horizontal member separating a door from a window panel above the door, or separating one window above another.
Transom: Small window located above a door or another window.
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.
Triple glazing:
Three panes of glass with two air spaces between, com¬monly consisting of an insulating glass with a separate storm sash. Also available in an insulating window in a single frame.
Triple window:
Generally refers to any tripartite group of windows with square heads. Found on Colonial Revival houses. Units suggest Palladian windows but are less expensive to construct.
U-Value:
Measurement of heat transfer through a given mate¬rial. The lower the U-Value, the better the insulation value.
Venetian window:
Same as Palladian window.
Vertical sliding window:
One or more sash that move in a vertical direction.
View sash:
Picture window with the lights divided by muntins.
Venting unit:
A window or door that operates or opens for ventilation.
Wash cut:
Beveled cut in a stone sill to divert water.
Water drip:
Molding sometimes used on exterior surfaces of an in-swinging casement sash to prevent water from being driven over the sill.
Weather-stripping:
A strip of resilient material applied to the perimeter of the sash and/or frame of a window or door to minimize the potential for water and air infiltration.
Weep cut (also drip cut):
Groove in the underside of a horizontal board or masonry unit which projects beyond the wall service below to prevent water from moving back toward the wall surface.
Yoke:
Head window jamb in a box window frame.
Yorkshire light:
Window with one or more fixed sash and a horizontally moving sash.
Windload:
The force exerted on a surface by moving air.