Awning window Awning windows have top-hinged sashes that swing open and upward.
Balance Pocket The space in which the balance system operates.
Balance System A mechanical system that assists in lifting the window sashes and keeping them in place. More specifically, it is a device for holding vertically sliding sashes in any desired position through the use of a spring or weight to counterbalance the weight of the sash.
Bay Window A bay window projects away from the wall in a building, and extends to the ground. The bay window has three lites, and is usually angled at 30 or 45 degrees when the windows are connected to each other.
Bow Window A window that incorporates the use of small angle mullions, usually angled at 15 degrees or less to connect anywhere from three to seven lites together. This gives a rounded effect to the unit by projecting from the wall in the shape of an arc, commonly consisting of five sashes.
Cam Lock The locking system that keeps the window closed by pulling the sashes together when placed in the locked position.
Casement Window Casement windows project outward and can be entirely opened. They are hinged at the sides. Casement windows open up the room to more air and light, and the inward closing action makes a tighter weather seal in windy conditions.
Deadlite A piece of glass or IG unit with a sash profile around it, so it is not set within the main frame of a window unit.
Double Hung Window A window with two vertically moving sashes, each responsible for closing a different part of the window. Both the upper and the lower sash are operable along the two tracks. A half or full screen is located on the outside of the frame in its own track.
Double Slider A sliding window with two moving sashes.
Double Strength Glass A thicker pane of glass, 1/8 of an inch thick.
Drip Cap A horizontal molding to divert water from the top casing, so that the water drips beyond the outside of the frame.
Dual-Night Vents Limits window movement, allowing them to only open up to a certain point. Serves as security hardware.
Egress Windows A window which meets the opening size requirements set by the Uniform Building Code for emergency exiting requirements.
Entry Door A door that is hinged from either side.
Equalite In a single or double hung window, the upper and lower sections are equal in height.
Extrude To shape or form by forcing through an opening, or by heating metal to a semi-plastic condition through dies by the use of hydraulic power. For example, extruded metal, extruded rods, or extruded shapes.
Fiberglass A composite material made by embedding glass fibers in a polymer matrix. May be used for diffusing material in a sheet form, or as a standard sash and frame element.
Frame A structure for encasing and bordering that gives shape or support to a window.
French Door A door that is hinged from the outside and consists of two pieces.
Garden Window The Garden window projects outside the house, where the top, the sides and the front made of glass. This type of window is usually found in the kitchen.
Geometric Windows Specially designed windows classified as either atraight geometrics such as rectangles, triangles, trapezoids, octagons, pentagons, etc. or radius geometrics such as half-rounds, quarter-rounds, full-rounds, ellipses, brows, etc. Commonly used to personalize the home and make architectural statements.
Grids Roll-formed, rectangular, metal tubes which are suspended between two panels of glass. Primarily used as decorative horizontal or vertical bars to create the appearance of the sash being divided into smaller lites of glass.
Hardware A window’s hardware includes locks, rollers, weather-stripping, balance systems, cords, chains, fasteners, hinges, pivots, lifts and pulls, and sash weights.
Head The top portion of the window where the sash meets the window header.
Hinge A movable joint that enables a window to swing open.
Hinged Patio A hinged patio consists of one moving part and one stationary part, with a hinge in between.
Hopper Window Hopper windows open inward, and can be entirely opened. The window is hinged at the bottom.
Intercept Spacer A spacer that is steel based, with a specially u-channel design to reduce the number of conduction paths.
Jamb The sides or vertical sections of a window frame.
Latch A device that holds a window shut, such as the metal device at the meeting rail of a double-hung window, or the fastener mounted on the stile of a casement window.
Lift Handle A handhold for raising and lowering the sash. Handle implies that it is not continuous across the sash.
Lift Rail The part of the sash of a window used to raise or lower the window. Applicable only to single hung and double hung windows. Rail implies that the handhold is continuous across the sash.
Lite A unit of glass in a window that allows light to pass through.
Lock A fastening device in which a bolt is secured and can be operated by a key to secure a window or patio door when in the closed position.
Main Frame The head, sill and jambs sections of a window.
Meeting Rail The horizontal members of a double-hung window which come together.
Meeting Rails The area of a window where two sashes meet and locks are positioned.
Member Any structural part of a window such as a rail or stile.
Mesh Fabric made of either fiberglass or aluminum that is used to make screens for windows and doors.
Molding A relatively narrow strip of wood used to conceal a joint or to emphasize the decoration of a structure.
Muntin Grilles Wood, plastic or metal grilles designed for a single-lite sash to give the appearance of muntins in a multi-line sash, but are removable for ease in cleaning the window.
Operator A crank-operated device for opening and closing casement or jalousie windows.
Oriel Window A single or double hung window which has an uneven top and bottom sash that increases the sightline from inside the house. Most oriels have a 60/40 configuration.
Patio Door A glass door that slides open and closed on adjustable tandem rollers. Available in two or three lite configurations with the operable panel available in any position.
Pattern Grid
Picture Window The picture window has no moving parts. It is one large inoperable sash.
PVC (Poly Vinyl Chloride) The most common plastic used in modern construction. It is an extruded molded plastic material used for window framing and as a thermal barrier for aluminum windows.
Radius Window This window is the same as a single hung window except the top portion is oval, not straight.
Rail The horizontal sections of the sash.
Retrofit Window A window designed to replace an existing window without removing the original frame.
Sash The part of the window that moves, whether it be up or down, left or right, or in and out.
Sash (pivot) Alignment System An exclusive, hinge-type system used on hung windows. This system attaches the sash to the balance, creating perfect alignment between the sash and frame, while allowing the sash to tilt inward for cleaning.
Sash Stop A molding that covers the joint between the window sash and the jamb to stop the travel of the sash at the top and bottom of the window.
Screen A woven mesh of metal, plastic, or fiberglass stretched over a window opening to permit air to pass through but preventing insects from passing through.
Sculptured Grid
Sill The horizontal members of the bottom portion of the window frame. Usually made from aluminum, swiggle, composite materials or stainless steel.
Simulated True Divided Grid A grid that is designed to achieve the look of a true divided grid, without actually dividing the panes of glass. It is actually an external grid on one large glass unit.
Single Hung Window Only the bottom sash of the window operates while the upper sash is stationary.
Single Slider A sliding window with one moving sash.
Slider Sliding windows and doors with sashes that only move horizontally, along grooves or tracks, while other parts remain stationary.
Sliding Patio
Spacer A part that seals two panes of glass in a double-pane window system, and forms a dead air space between them.
Stile The vertical edges of a window, door or screen’s sash panel that connects the lock rail and the lift rail.
Stop The molding on the inside of the window frame against which the window sash closes, or in the case of a double-hung window, the sash slides against the stop.
Super Spacer A spacer that is foam and fiberglass based. This is the least conductive spacer.
Sweep Lock A sash fastener located at the meeting rails of a double-hung window which rotates and clamps the two rails closer together.
Tilt and Turn Window The tilt and turn window is the same as a single hung window, except the sash can be tilted or turned in addition to the normal up and down motion.
Tilt Latch Pull A latch that allows the sash to tilt in so that the outside of the glass can be cleaned.
Triple Pane A unit with three pieces of glass separated by two spacers. These windows are designed for areas with prolonged exposure to extreme heat or cold.
True Divided Grid A grid that divides a window pane into a number of small mini-panes that are sealed and completely separated from each other. Only available in wood products.
V-groove Grid
Vinyl Extrusions Just like the aluminum frames, vinyl window frames are extrusions (prefabricated cuts). But because vinyl is not as rigid as aluminum, internal hollow chambers are often added to provide strength, and increase performance.
Weld To join together by applying heat, pressure or sometimes with an intermediate filler material that has a high melting point.
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Astragal An interior molding attached to one of a pair of doors or side-hinged windows in order to prevent swing through. Also used with sliding doors to ensure a tighter fit where the doors meet.
Bottom Rail The lower, horizontal member of a window sash.
Boxed Mullion A hollow mullion between two double-hung windows to hold the sash weight.
Butterfly Clip An tool used as a jamb adjuster for the installation of replacement windows. Also known as a head jamb adjuster or a wafer adjustment screw.
Cable Support An installation tool used to support the weight of a bay or bow window when installed in a house.
Capillary Tubes Small hollow tubes, which penetrate the spacer system of an IG unit before assembly. They allow pressure equalization during the delivery of the window from the manufacturer to the shipping and installation locations. Since the insulating glass unit is not permanently sealed, the air space cannot be filled with Argon gas yet. Thus, capillary tubes are used.
Casing (trim) Exposed molding or framing around a window or door, on either the inside or outside, to cover the space between the window frame and the wall.
Caulking A mastic compound for filling joints and sealing cracks to prevent leakage of water and air. This compound is commonly made for silicone-bituminous-acrylic or rubber-based materials.
Coil Trim Installation This is a retrofit installation only applicable to aluminum or steel windows. During this installation process, windows arrive without the fins, so they are custom-built at the job-site. This process requires more work and is more expensive.
Dry Glazing A form of glazing in which the glass is secured in the frame with a dry gasket, wood stops, or metal stops instead of with a glazing compound.
Drywall A wall or ceiling constructed of prefabricated material.
Exterior Glazing Exterior glazing is sealed from the outside of the building. This is easily removable from the outside of the window, which increases the risk of break-ins.
Fabricate To construct by combining or assembling diverse, typically standardized parts.
Fasteners Devices such as nails and bolts, for jointing two parts together.
Fenestration The placement of window openings in a building wall, and controlling the exterior appearance of the building.
Glazing The act of installing any glass into any frame or structure by sealing the glass unit into the frame with glazing beads.
Glazing Beads Removable trim pieces that hold the insulating glass unit in place and cover the edges of the glass.
Glazing Channel A groove cut into the sash during installation for the mounting of the glass.
Headboard The top wooden board used when installing a bay or bow window, to connect all of the windows together in a fixed location.
Header The supporting member or wood beam above the window opening that transfers the building weight above to the supporting wall structure on each side of the window.
Infuse To pour in.
Interior Glazing Glazing that is sealed from the inside of a building.
Knocked-Down Unassembled parts of a window frame pre-manufactured for assembly at a later date on the job site.
Miter Joint Two members joined at an angle, usually 45 degrees.
Moisture Barrier A material that prevents the passage of water vapor from one space to another. Polyethylene sheet is commonly used as a moisture barrier.
Mullion A vertical or horizontal connecting unit between two or more window units or sliding glass doors.
Muntin A secondary framing member (horizontal, vertical or slanted) to hold the window panes in the sash.
Nailing Fin A lip around the perimeter of the window frame that provides a convenient nailing surface for window installation. Used only with new construction types of installation.
Nail-On Fin Installation A new construction installation that is generally used when a house is in the process of being built. It is not used for replacing existing windows.
New Construction Installation Installation that requires putting in original, new windows.
Pane A sheet of glass for glazing a window. After installation the pane is referred to as “lite” or “window lite.”
Parting Bead A vertical strip on each jamb that separates the sashes of a double-hung window.
Retrofit Installation Installation that requires replacing existing windows.
Sealant A compressible plastic material used to seal any opening or junction of two parts, as between the glass and a metal sash. Sealant is commonly made of silicone, butyl tape or polysulfide.
Single Glaze One pane of glass placed in the sash.
Stucco Plaster of any kind used as a coating for walls (for example, cement, sand, limestone).
Swiggle Spacer A flexible spacer that is aluminum or butyl-based. This is a poor spacer because metal is a conductive material, so it heats and cools quickly. This causes rapid expansion and deterioration of the window, and seal failure and separation of the glass.
Transom A horizontal member, separating a door from a window panel above the door, or a beam separating one window from another.
Wet Glazing A silicone-based substance used to secure and seal the glass to the sash.
Wood Stop  Wood trim on the interior of the frame used for finishing windows. Performs the same function as vinyl.
Z-bar Installation A retrofit installation only applicable to existing aluminum windows. During the installation process, the gap between the old and new frames is covered.
Art Glass Leaded glass that forms a design by combining pieces of colored glass and then sealing them with leaded strips.
Insulating Glass Two panes of glass that sandwich a dead air or argon gas space. Primarily used to lower heating and cooling costs.
Laminated Glass Glass that is designed to decrease the noise level transmitted by the window. A special laminating film is applied to one of the panes of the insulated glass unit.
Obscure Glass Any textured glass (frosted, etched, fluted, ground) used for privacy, light diffusion or decorative effects, that permits light to pass through without displaying a clear image. Mostly used in bathrooms and showers.
Safety Glass
Single Pane A unit with one piece of glass. A single pane window has little insulating value because it only provides a thin barrier to the outside and can account for considerable heat loss and gain.
Single Strength Glass A thin pane of glass, 3/32″ thick.
Tempered Glass Strengthened or reinforced glass that is designed to break apart into small pieces when broken, rather than shatter completely. Also known as safety glass.
Tinted Glass Glass containing chemicals with gray, bronze or blue-green tint that absorb light and heat radiation, reducing glare and brightness. As a result, this glass reduces the amount of sunlight entering through the window and can be combined with LowE2 coating for more solar control.
Wood Stop Installation A retrofit installation only applicable to existing wood windows. During the installation process, original wood stops are removed, the new window is installed, and new wood stops are replaced.