Window and Door Terminology

 

A

Airspace: The area between two or more sheets of glass in a window or door.
Airspace Grilles: Aluminum bars sealed in the insulating airspace between the two panes of glass in a window or door.
Argon Gas: Is an inert gas that is inserted between the panes forming a sealed glass unit. This gas increases the energy efficiency of the sealed unit
Awning: A single-sash window that's hinged at the top of the sash and uses a handle crank that allows the bottom of the window to swing out towards the exterior of a home.

B

Balances: A system used in double- or single-hung tilt windows that holds the operating sash open in any position and allows the window to be opened or closed with minimal effort.
Bay Window: A picture window combination consisting of two or more windows placed at 30-, 45- or 90-degree angles allowing it to extend outside a home's exterior and create an open space on the interior. The individual units in a bay window usually feature both fixed and operating sash.
Bottom Sweep: A specially designed, flexible fin attached along the bottom of a door to create a tight seal when the door is closed to prevent air and water from entering a home.
Bow Bay: A bay window combination featuring a series of four or more windows gently angled to create a curved shape that extends outside a home's exterior. Generally, the individual window units on the far ends feature an operating sash.
Box Bay: A bay window combination featuring two sash set at a 90-degree angle.
Brick Mould: The decorative moulding surrounding the exterior of a window or doorframe to provide them with the traditional look of a wood window or door.
Brush Seals: Are brush type seals that are used on the sash edges of casement and awning windows. They are the primary seals that are attached to the edges of the sliding sashes of horizontal and vertical slider windows.

C

Caming: The ornamental material used to hold decorative pieces of glass in place. Caming is typically made from brass, lead or zinc in a variety of finishes.
Capping: Formed aluminum, which is used to cover exterior wood frames and brick mould.
Casement: A single-sash window that's hinged on one side and uses a handle crank that allows the window to swing open to either the right or the left, towards the exterior of a home.
Casing: Interior trim that is attached to the jamb or jamb extension of a window or a door. The casings surround the window and cover the frame.
Check Rail (Meeting Rail): The horizontal sash members on a double- or single-hung tilt window or the vertical sash members on a slide/by window that come together when the windows are closed.
Circle Top (Round Top): A direct-set window in the shape of a quarter circle, a half circle, a half ellipse, an arch top, a full ellipse, a full circle or a gothic arch top that can be used alone, in combination or stacked above another window or door.
Clad: Refers to the portion of a wood window or door that's covered with aluminum or vinyl on the exterior side of the frame and/or sash.
Compression Seals (sometimes called "bulb"): Are tubular seals are typically used in casement and awning windows to prevent air penetration.

D

Desiccant: A material used in window and door spacer bars that absorb water and helps remove moisture.
Direct-Glaze: A sash-less window that doesn't open and features the glass glazed directly into the window frame. A direct glazed picture window can also feature a simulated sash designed to match the look of two flanking windows with operating sash.
Door Panels: The swinging or sliding portion of a patio door, consisting of the top and bottom horizontal rails, the left and right vertical stiles and the glass. Also, the central portion of the entry door that swings open either inward or outward, typically consisting of panel skins made from fiberglass or heavy-duty steel.
Double Glazed: A sealed glass unit that consists of two layers of glass separated with a spacer.
Door Rollers: Two sets of tandem stainless steel wheels with ball bearings that allow sliding patio doors to smoothly open and close using the minimum of effort.
Double-Hung Tilt: A window where both the upper and lower sash slide up and down to allow air into the room. The sashes are designed to tilt into a room for cleaning on both sides from inside a home.
Drip Cap: A formed-aluminum or vinyl accessory piece that's installed along the top of clad windows and doors that allows water to run off of the unit instead of seeping into the unit and a home.

E

End Vent Slider: A three-sash window featuring a stationary center sash and two flanking sash that open and close by sliding sideways.
Eyebrow: A round top window consisting of a partial radius head that's typically used above a window or door.

F

Finger Joint: Is the finger groove extensions of wood that fit into each other when two pieces of wood are joined together to extend the length.
Finger Lifts: The two indentations on the lower horizontal rail of a tilt window's bottom sash allowing you to easily slide the sash up and down.
Finial: An ornamental piece that accents a patio or entrance door's hinge pin to create a stylish appearance found in Spanish Colonial architecture.
Frame: The surrounding outside portion of a window or door composed of the head at the top, the side jambs and the sill at the bottom.
French Sliding Patio Doors: A patio door style with the look of a traditional French patio door featuring taller top and bottom rails. One or more door panels open and close by sliding sideways.

G

Garden Bay: A traditional bay window combination with a direct set window that's flanked by operating or stationary casement windows placed at a 90-degree angle to the interior wall. This particular bay window combination has an overhead glass pane that allows sunlight to flow directly into the window area. This style of window is also known as a Green House window.
Glazing: The glass portion of a window or door. Also refers to the actual process of installing the glass in a sash, frame or door panel.
Grilles: A decorative pattern on a window or door consisting of horizontal and/or vertical bars that divide the larger sheet of glass into smaller panes. Grille types include Simulated Divided Lite (SDL), True Divided Lite (TDL), Grilles in Airspace (GIA) or Grilles Between Glass (GBG), perimeter grilles and stick grilles.
Grilles in Airspace: Also referred to as airspace grilles or grilles between glass, these are aluminum muntin bars sealed in the insulating airspace between the two panes of glass, making cleaning easier.

H

Handleset: The hardware portion of a door consisting of a core, turning mechanisms, a handle or knob, a strike plate and a lock plate.
Hardware: The locks, crank handles and hinges on windows and doors used to operate and secure them.
Head / Header: The horizontal piece forming the top of the frame on a window or door.
Hinged Patio Doors: A patio door style featuring two panels with hinges on the outer sides that allow the door panels to swing open either inward or outward from the center. Center-hinged, or French, patio doors feature one fixed and one operating door panel with hinges between the panels to allow one panel to swing open over the other. This style of patio door is also known as a Garden Door.
Hinges: The hardware portion of a door that allows one or more door panels to swing, inward or outward, from the sides or from the center.

J

J-Channel: An accesssory that attaches to a window for a finished edge where exterior siding is used.
Jamb or Side Jamb: The left and right vertical pieces forming the frame on a window or door.
Jamb Extension: An extra window frame piece added to the jamb that extends the frame to match the precise thickness of a wall.
Jamb Liner: The tracks located inside the jambs of a double- and single-hung window on which the sash slide up and down.

K

Krypton Gas: Is an inert gas that is inserted between the panes forming a sealed glass unit. This gas increases the energy efficiency of the sealed unit.

L

Lockset: A door's complete lock system consisting of the lock mechanism, knobs, keys, plates, strikes and other accessories.
Low E: A term meaning low "emissivity". Emissivity is a property that's unique to materials such as glass, which light can freely pass through. Low describes the filtering out of the part of the light spectrum that transmits heat.
Low E Glass: Glass with a microscopic coating applied to one or more surfaces to provide greater energy efficiency and UV protection that helps reduce the fading of artwork, curtains, furniture, rugs and floors in a home.

M

Meeting Rail: The horizontal sash members on a double or single-hung tilt window or the vertical sash members on a slider window that come together when the windows are closed.
Mull (Mulled or Mulling): The actual piece used to attach two or more window and/or door units together to form a combination. The process of joining the units to each other.
Mull Cover: An exterior connector that joins two windows together with a finished edge to cover the space between two units. It also helps prevent air and water from infiltrating into your home.
Mull Post: The structural post between the entry door and its sidelite that provides strength to the entire door unit.
Muntin Bars: The narrow, horizontal and/or vertical bars that form the decorative grille pattern on a window or door.

N

Nailing Fin: A leg of the extended aluminum or vinyl exterior of clad units that forms a 90 degree angle to the window and is positioned flush against the sheeting of the building. Clad windows are easily secured in the rough opening by nailing through the fin into the sheeting and jack studs of the rough opening.

O

Operator Handle: The piece of window hardware used to crank the sash open on a casement or awning window.

P

Pane: A single piece of glass within a window or door.
Parting Stop: The portion of a window or sliding patio door that is screwed into a recessed channel to help provide better support for the sash or door panels.
Picture Window: A large, stationary window used to capture wide views of exterior landscape. Can be combined with other functional windows such as double-hungs and casements, and/or topped with direct-set or awning windows for enhanced views.

R

Rails: The horizontal framework members of a window sash or door panel.
Retractable Screen: A mesh fiberglass exterior piece on a window or door that rolls down from a concealed aluminum tube and keeps insects from entering the home. (Also see "screen")
Rosette: Corner blocks that are used in conjunction with casing trim.
Rough Opening: The opening in the wall where the window or door is to be installed, slightly larger than the size of the unit to allow squaring and shimming.
R-Value: A measurement of how much a material resists heat transfer. A higher R-Value means a greater insulating effect and a lower rate of heat flow.

S

Sash: The fixed or operating portion of the window consisting of top and bottom horizontal rails, left and right vertical stiles, and the glass.
Sash Lock: The piece of window hardware that secures the sash to the frame on a casement or awning window, or secures two sashes at the meeting rail on a tilt or slide/by window, when the window is closed.
Sash Pulls: The two routed indentations located on the left and right outside vertical stiles of a slide/by window's sash allowing you to easily slide the sash left or right.
Screen: The framed, mesh fiberglass exterior piece on a window or door that keeps insects from entering the home. (Also see rectractable screen)
SHGC (Solar Heat Gain Co-Efficient): Is a measure of how much of the sun's heat is transmitted through glass. A product with a low SHGC will help to block heat and reduce cooling loads in hot weather; a product with a high SHGC will be more effective at harnessing solar heat in cold weather.
Side Jamb: The vertical left and right members of a frame on a window or door.
Sidelite: The narrow fixed or operating sash consisting of either steel or wood stiles and rails, glazed with clear or decorative glass and matching the sight lines of the entry door. Sidelites are typically joined to the entry door on one or both sides.
Sill: The horizontal piece forming the bottom of the frame on a window or door.
Simulated Divided Lite (SDL): Windows with grilles adhered to the interior and exterior of the window glass, in a variety of decorative options, to simulate the look of True Divided Lite.
Single-Hung: A window with two sash, where the bottom sash slides up and down and the top sash is fixed. Many single-hung windows also have a tilt-in option on the bottom sash for easy cleaning and removal.
Sliding Patio Door: Up to four glass door panels that slide on tracks giving fast, easy access to the outdoors.
Spacer: A bar used to separate the panes of glass in an insulating window.
Stacked: When two or more window units are joined vertically.
Stationary: A non-operating sash, panel or unit.
Stiles: The two vertical pieces of the window sash or door panel outside of the glass or embossing.
Stop: molding set in place to hold, position or separate window parts.
Sweep: A piece of vinyl weather stripping along the bottom of the door that makes contact with the threshold to provide a tight seal against air and water infiltration.

T

Tempered Glass: Float glass that is heated and then cooled rapidly to make it several times stronger than annealed glass. Standard in all doors, tempered glass is safer than annealed glass because when it is broken it falls into pebble-like pieces without sharp edges.
Threshold: The bottom area of the doorframe that you step over when entering or exiting through a doorway.
Tilt: Both sash of this window slide up and down to allow air into the room, as well as tilt into a room for easy cleaning on both sides.
Transom: A window stacked above another window or door.
Triple Glazed: A sealed glass unit that consists of three layers of glass separated with two spacers.
Triple Slider (End Vent): A three-sash window featuring a stationary center sash and two flanking sash that open and close by sliding sideways.
True Divided Lite (TDL): Individual lites of single glass or insulating glass, separated by muntin bars.

U

U-Value: A measurement of how much energy a material conducts. The lower the U-Value, the greater the insulating effect.
uPVC: Unplasticised polyvinyl chloride

W

Warm Edge Spacer: Refers to the type of spacer material used to separate panes of glass in an insulated window unit. If the material conducts less heat or cold than an aluminum spacer at the edge of the glass, it is said to be 'warm edge'.
Weather Stripping: A strip of resilient material designed to seal the sash and frame members to reduce air and water infiltration.
Weep System: A special interior formation of the sill designed to channel water away from your home to prevent the moisture build-up that leads to rotting.