Glossary

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AAMA – American Architectural Manufacturers Association, a national trade association that establishes voluntary standards for the window, door, and skylight industry.

Active – In a double door assembly, it is the door that is used more frequently. Also, the active door needs to be opened before the passive door can be opened.

Active Panel - Primary operating door panel.

Air Infiltration – Amount of air leaking in and out of a window through cracks in the framing or past the weather stripping. It is measured in cubic feet per minute per square foot (cfm/ft²).

Aluminum Surround - The aluminum frame around a screen or energy panel.

Apron – A piece of casing or decorative trim installed against the wall immediately beneath the stool of a window.

Argon Gas – An odorless, colorless, tasteless, nontoxic gas that is six times denser than air. It is used to replace air between the glass panes to reduce temperature transfer.

Assembly - Single units mulled together.

Astragal – On a double door, the milled component attached to the meeting edge of the inactive active (passive) panel, allowing the two to lock together.

Authentic Divided Lite (ADL) - Also known as true divided light. Single or insulating glass, individually glazed between the muntin bars.

Awning – A combination of frame and sash, hinged at the top of the vertical jambs which allows the unit to pivot from the top with the sash opening to the exterior of the building.

Balance – Device for counterbalancing a sliding sash usually associated with a double hung window, so sash may be held open at any given position. It is usually a system of cords, weights, springs or spiral devices.

Ball-Bearing Hinge – A heavier duty hinge verses the standard pin hinge, with bearings supporting the pivots. Ball-bearing hinges are usually used for heavy doors that will be in commercial or industrial use.

Bay Window – Three or more window units attached together to project outward from a building wall. Bay angles vary; most common are 30°, 45° and 90°.

Bi-Fold – A door that is capable of being folded into two or more parts, as with doors that are hinged together.

Blindstop - The frame member on a double hung window located between the jambs and the casing. The blindstop forms a rabbet that supports either a storm sash or screen.

BOCA – Building Officials and Code Administrators, one of the three model code groups in the U.S. that has now merged into the International Code Council.

Bottom Rail – On a window sash or door, it is the bottom horizontal component that supports the weight of the glass or the panel.

Bow Window – A combination of four or more window units in a rounded formation that project outward from a building wall.

Box Bay – A combination of window units that projects to the exterior. Usually features a large center unit with two flanking units at 90 degree angles to the wall.

Box-Framed – In door and sidelite assemblies, a term used to differentiate door and sidelight units which are first framed as separate units, with heads and sills separate and non-continuous.

Brickmould Casing (aka: BMC) – An exterior moulding of window and door frames that abuts the exterior facing material of the structure. The casing serves as the boundary moulding for brick or other siding material and also helps to form a rabbet for screens and/or storm sash.

Caming – Metal parts of leaded glass design. Metal options include lead, brass, copper, zinc, or patina.

Cam Lock - A lever operated lock which is used to prevent intrusion through the sash.

Cam Pivot - A zinc pivot pin attached to the top and bottom sash stiles of double hung units (bottom sash on single hung units). Cam pivots rest on the clutch system of the balance tube assembly which allow opening and closing of the sash.

Capping – A term to describe the covering of exterior trim with roll-form aluminum.

Casement – A window hinged on one side and is typically operated using an interior hand crank.

Casing – Milled wood attached to the interior around a window or door to cover the gap between the frame and the wall.

Caulking – A soft semi-liquid material used to seal cracks around a window or door frame adjacent to the wall opening.

Check Rails - On a double-hung window, the bottom rail of the upper sash and the upper rail of the lower sash, where the lock is mounted.

Circlehead - A generic term referring to any of a variety of window units with one or more curved frame members, often used over another window or door opening.

Cladding – Any material locked to the outside faces of doors and windows (exterior skin) to provide a durable, maintenance free exterior surface.

Clear Jambs – Natural wood frames without paint or primer applied which appear to be made of full-length pieces of stock.

Clerestory – A window in the upper part of a high-ceilinged room that admits light to the center of the room.

Combination Storm - A wood or aluminum storm sash with self-storing screen and operation glass panels.

Combination Window - A wood or clad wood frame storm sash with self-storing screen. Bottom glass panels such as those installed on a double hung operates by moving the plungers in and sliding the glass panel up to the desired position. Side glass panels such as those installed on gliders, slide to the left or right to the desired position.

Composite – A solid material composed of two or more substances.

Compression Jambs – Spring-loaded liners in window jambs that assist in maintaining a weather tight seal between window sash and frame which can be compressed allowing you to tilt the window sash for cleaning.

Condensation – A condition caused by warm moist air coming into contact with a colder object creating moisture on the colder surface. A large difference in the temperature of either side of a window and humid air present on the warmer side will cause condensation to appear.

Continuous Sill – Used for a type of door and sidelite unit in which the unit has full width top and bottom frame parts, and an internal post or posts separating sidelites from the door panel.

Core – The material inside the door to provide either strength or fire rating. Some types are corrugated, honeycomb paper, particleboard, wood stave, mineral fiber, polyurethane, or polystyrene.

Cottage Window – A double hung window with unequal sash. The top sash is shorter than the bottom sash.

Cripples – The short framing members used to frame under the sill or above the header in a rough opening for a window or door.

Curb - A watertight wall or frame used to raise slope glazing above the surface of the roof as a preventative measure against water leakage from melting snow or rain run-off.

Cylindrical Lock – Lock hardware which mounts into a door which has been prepared with a bored hole or holes through the door slab and also through the edge.

Daylight Opening (aka: DLO) - The width and the height of the visible glass.

Deadbolt (aka: DB) – A lock used to secure a door closed, the latch being driven from the door into a receiver in the jamb or frame.

Depth of the Jamb - The point where the exterior casing ends to the point where the interior casing begins.

Direct Pressure (aka: DP rating) – The pressure a product is designed to withstand. This value is a measure of a product’s capacity to withstand the forces of wind loading, in both positive and negative directions, while it is closed and locked.

Direct-Set – Refers to a window with non sash. The glass is glazed directly into the frame and is stationary.

Divided Lites - Division of light by the use of muntin bars.

Door Lite – An assembly of frame and glass panel, which when fitted to a door in a formed or cut-out hole, creates a door with a glass opening.

Door Slab – A door only, no frame included.

Dormer – A space which protrudes from the roof, usually including one or more windows.

Double Glazing – The use of two panes of glass sealed together in a product to increase energy efficiency.

Double Hung – A window with two movable sash which operate vertically. Single hung windows operate the same as double hung windows, but the upper sash is fixed in place.

Double Rafter- The doubling (side by side) of the roof members to reinforce an opening in the roof for a slope-glazing installation.

Drip Cap – A formed aluminum or vinyl piece which is installed at the top of windows and doors that allow water to run off the casing of the unit instead of seeping around the casing and into the unit.

Drywall Opening – A rectangular opening in a wall, usually an interior wall, prepared to the size necessary to receive a pre-hung assembly.

Dummy Cylinder – A lock without a latch, typically used for the passive door panel of a double door unit, so that the hardware appears equal to that used on the active door panel.

Edge Bore – The hole bored through the edge of a door to allow for the latch to be installed.

Egress Code – Code that requires a minimum opening of a window for persons to exit or firefighters to enter a building.

Elliptical – Window that is elongated and radius at the top.

Energy Panel - A piece of glass annealed or tempered, and finished on the edges by a surround. Energy panels are applied to windows or doors and rest on the glazing stop. They offer added energy efficiency.

Energy Star – A program sponsored by the U.S. Department of Energy that established minimum performance standards for windows to be recognized as energy efficient.

Escutcheon – A stamped decorative plate, to trim the shaft of a door knob or deadbolt latch, to trim the opening where the shaft or latch adjoins the face of a door.

Etched Glass – Glass in which a decorative pattern is engraved by means of chemical action or mechanical sand-blasting.

Extension Jamb – A milled piece used to increase the depth of the jambs of a window frame to fit a wall of any given thickness.

Extrusion – The process of forcing heated materials such as aluminum or vinyl through a die to produce specified shapes.

Faceplate – The plated or solid metal trim piece, usually about 1 x 2-1/4 inches, housed flush into the edge of a door, through which projects the latch of a lock or deadbolt.

Fenestration – Originally, an architectural term for the arrangement of windows, doors, and other glazed areas in a wall. Has evolved to become a standard industry term for windows, doors, skylights, and other glazed building openings.

Finger-Joint (aka: FJ) – A way of joining short sections of boards together by cutting a set of complementary rectangular cuts in 2 pieces of wood which are then glued end to end to make a longer board.

Fire Door – Fire doors are designed to meet standards for fire ratings of 20, 30, 45, 60, or 90 minutes. The specific rating is achieved through the application of special door cores and framing materials.

Fixed – Windows that are not operable.

Flanker – A term used to describe the side parts of a multiple combination opening.

Flashing – A strip of material that diverts water away from a window, door, or skylight.

Flat Casing - Flat, surfaced on four sides, pieces of pine of various widths and thicknesses for trimming door and window openings. The casing serves as the boundary moulding for siding material and also helps to form a rabbet for screens and/or storm sash or combination doors.

Flush-Glazed – A type of glazed door which has its glass perimeter moldings flush with or set down from the face of the surrounding door.

Fogging – A film left on an interior surface of a sealed insulating glass unit due to extreme weather conditions or seal failure.

Foot Bolt – A steel pin housed in a door bottom edge or astragal, with a latch mechanism, which can be driven down to project into a receiver socket or hole in the floor or threshold, to better secure the door when closed.

Frame – In window and door assemblies, they are the perimeter members which the sash or door is hinged and latched to.

• All-vinyl frames - Among the least expensive options and easiest to maintain. The never need to be painted.
• Solid wood frames - Can be painted any color but require a lifetime of maintenance to ward off rot and keep paint looking fresh. The price varies with quality.
• Clad wood frames - Wood frames covered on the exterior with a skin of generally aluminum or vinyl. They generally cost more than solid wood but are easier to maintain. Aluminum tends to be stronger and is available in more color options.

Frame Expander - A flat aluminum extrusion used in conjunction with the 90 degree frame expander to provide a flat casing appearance for clad units.

French Casement - A casement styled unit with two sash in one frame providing a sense of openness unrestricted by a vertical mullion or stiles when both sash are open.

French Hinged Door – Hinged door(s) which have wider stiles and rails around the glass.

French Sliding Door – A sliding door which has wider stiles and rails around the glass, giving the appearance of French hinged door.

Full-Frame Replacement – A replacement method where the entire old window is removed along with the interior and exterior casing around the window exposing the rough opening of the building.

Fusion-Weld – A term used for a type of corner construction, used with vinyl and other types of windows and doors, in which a small amount of material on the ends of two pieces are melted or softened, then pushed together to form a single piece. This also is referred to simply as a welded corner.

Galvanized – An adjective used to describe steel which has been zinc-coated. Galvanized steel is resistant to corrosion.

Gasket – A strip of flexible material that prevents air and water from penetrating or passing through joints between parts.

Glass Size - The measurement of the actual glass, not the visible glass.

Glazing – Installing glass into windows and doors.

Glazing Bead– A plastic or wood strip of molding that overlaps the gap between the glass and sash which holds the glass in place.

Glazing Compound - A pliable substance applied between the window sash and the lights of glass to seal against the element and sometimes to adhere the glass to the sash.

Glazing Stop - The part of the sash or door panel which holds the glass in place.

Glazing Tape - A two sided adhesive tape placed between the glass rabbet and the glass and/or the glazing bead and glass of some unit types.

Glider (aka: Horizontal Slider) – A window with a moveable sash that slides horizontally.

Grilles (aka: muntins, grids) – Wood muntins fastened to the interior of the sash to create the effect of divided lites, removable for easy glass cleaning.

Grilles Between the Glass (aka: GBG) – Aluminum flat or contour bars inserted between two pieces of glass that divide the glass visually. Because the grille is between the glass, grilles do not become misplaced or damaged. Cleaning is easy without small panes of individual lites.

Grooved Glass – Glass which has been decorated with abrasively-routed recesses. Grooving can give a single piece of glass a multi-paned look.

Handing – A term used to describe the right or left hand operation of a window or door.

Header – A horizontal framing member installed above a door or window to transfer the building's load from above the opening to the supporting wall structure on either side of the opening. A properly sized header keeps the structure from sagging or worse yet, collapsing at the window or the door opening. Header sizes are based on opening size and building codes.

Head - The main horizontal member forming the top of the window or door frame.

Head Board - A flat board cut to fit the contour of a bow or bay window and installed between the head jambs and the flat wall surface to finish off that area which would normally be ceiling.

Head Bolt – A steel pin housed in a door top edge or astragal, with a latch mechanism, which can be driven up to project into a receiver socket or hole in the head jamb, to better secure the door when closed.

Header - A heavy beam extended across the top of the rough opening to prevent the weight of wall or roof from resting on the window frame.

Head Jamb – The horizontal top frame member of a window or door assembly.

Heat Gain – Heat transfer from the outside to the inside of a structure by means of conduction, convection, and radiation through all surfaces of a house.

Heat Loss – Heat transfer from the inside to the outside of a structure by means of conduction, convection, and radiation through all surfaces of a house.

High-Performance™ Low-E4® Sun Glass – Andersen Corporation's brand name for a slightly gray-tinted low emissivity glazing system designed for southern climates or windows in rooms where heat buildup (solar heat gain) is a factor.

Hinge – A moveable joint enabling a window or door to swing.

Hinge Stile – The full-length vertical edge of a door which holds the hinges.

Historical - A term used to define a window or door product meeting requirements of historical renovation standards.

Hopper – Window with sash that swings inward from the top, usually located in basements.

Impact Resistant Glass - Single or double pane construction made up of laminated glass containing a .090 interlayer

Inactive – A term for a door panel fixed in its frame. Inactive door panels are not hinged and are not operable.

Insert Replacement (aka: Pocket Window) – Replacing windows where the old window frame, interior casing, and exterior casing are reused.

Inside Stop – On a wood window, a piece of wood trim attached to each side jamb that defines the inner edge for the lower sash channel.

Insulating Glass (aka: IG) – Two pieces of glass, with a spacer around the perimeter which keeps them separate, that is hermetically sealed to provide insulating characteristics. The sealed space may contain air or be filled with an inert gas, such as argon or krypton.

Inswing (aka: IS) – A term used to describe an exterior entry door unit for which, when the hinged door panel is opened, the panel swings into the building. Interior Casing- The casing trim used on the interior perimeter of the window or door.

J-Channel – Installed around or built-in to the side of a window or door, this channel is designed to accommodate the ends of siding pieces to provide a finished appearance.

Jack Stud - Framing members, generally 2x4’s, which form the inside of the window or door rough opening. They run from the sole plate to the header, which is supported by them.

Jamb Extension – A jamb-like member, usually surfaced on four sides, which increases or extends the depth of the exterior or interior window or door frame.

Jamb Depth – Width of a window or door from the interior to the exterior of the frame to meet construction wall thickness.

Jamb Liner – Thin strips of wood attached to the head jamb, side jambs, and sill to accommodate various wall thicknesses. Common jamb depths are: 4-9/16”, 4-13/16”, 5-1/16”, and 5-3/16”.

Jamb Stop – In exterior door frames, the molded-in rabbeted surface of a frame member against which the door panel would close and seal.

Keeper - The protruding, hook-shaped part of a casement window lock, which is mounted on the inside surface of the sash stile.

Kerf – The groove in a jamb or frame where the weather stripping is inserted into.

Kick plate – This is a protective plate applied to the lower rail of a door to prevent damage from daily wear.

Knocked Down (aka: KD) – Unassembled, as contrasted to assembled or built-up.

Krypton Gas - Inert gas known for its ability to provide insulating properties in a small air space.

Laminated Glass (aka: Lami) – Two or more sheets of glass with an inner layer of transparent plastic to which the glass adheres if broken. Used for enhanced safety and security, as well as sound reduction.

Laminating - A method of gluing strips of thing clear wood to the lengthwise surfaces of finger jointed material to provide the appearance of clear stock.

Lift - Handle or grip installed on the bottom rail of the lower sash of a double-hung window to make it easier to raise or lower the sash.

Light Shaft - An insulated shaft built to direct the light from a roof window or skylight through the attic to the room below.

Lintel – Horizontal member (wood, steel, or stone) over a window or door opening to support the weight of the wall above.

Lite (also spelled light) – An assembly of glass and a surrounding frame, which is assembled to a door, or is integrally built into the door at the factory.

Lock Bore – For cylindrical locksets, the large through hole, usually 2-1/8-inches in diameter, bored near the door panel's lock edge, into which the lock mechanism is placed and installed.

Lockset - A complete door lock system comprised of the lock mechanism, together with knobs, keys, plates, strikes, and other accessories.

Low E Glass – Low E stands for low emissivity. The lower the emissivity the higher the percentage of long-wave radiation blocked thereby improving thermal performance. Low E glass is coated with a thin microscopic, virtually invisible, metal or metallic oxide layer. The primary function is to reduce the U-value by suppressing radiative heat flow. A secondary feature is the blocking of short wave radiation to impede heat gain. There are two basic types of Low E glass. The first, vacuum or sputter coated Low E, is referred to as soft-coat (See Low E II definition.) The second is pyrolytic Low E, commonly known as hard-coat (See pyrolytic definition).

Low E II Glass - A high performance Low E glass, providing the best winter U-value and warmest center glass. It offers significant improvement in reducing solar heat gain coefficient values, providing customer one of the coolest summer glass temperatures of all Low E products. Additionally, ultraviolet light transmission is greatly reduced. The Low E II coated glass products are specifically designed for insulating glass units normally as a second surface coating. See Low E and pyrolitic definitions.

Masonry Opening (aka: MO) – A brick, stone or block opening into which a window or door unit is installed including the outside casing.

Medium-Density Fiberboard (aka: MDF) – A wood-fiber composite used in a variety of window, door, and millwork applications.

Meeting Rail (aka: check rail) – The two horizontal members of a double-hung sash that meet and are locked together when the window is closed.

Meeting Stile – Either vertical member in a pair of gliding window sashes or door panels that meets and locks when the sash or panel is closed, comparable to the meeting rail on a double-hung window.

Miter – An angled cut across the end of a lineal part, usually done to join with a similarly cut part at a corner.

Mortise Lock – A lock fitting a rectangular shaped cavity in the edge of a door.

Mortise-and-tenon - A strong wood joint made by fitting together a mortise in one board and a matching projecting member (tenon) in the other.

Moulding- An ornamental exterior trim around the perimeter of a frame.

Mulling – The act of attaching two or more window or door units together. The joint is then finished with a mullion enter cap or mull trim.

Mullion – The vertical member of a sash, window or door frame between openings in a multiple opening frame.

Mullion Cover - A piece used to cover a space mull. Generally covers a range from 3” to 10”, depending on the size of the mullion.

Mullion Reinforcement - Used on multiple unit assemblies to improve structural performance.

Multi-Point Locking System – A locking mechanism installed on the operative panel(s)/sash to enhance security and performance. Operated with one handle and secures a window or door at two or more locking points.

Muntins - The actual bars that create a pattern in the window.

Nailing Fin – An accessory component or integral extension of a window or patio door frame that generally overlaps the conventional stud construction and through which nails are driven to secure the frame in place.

National Fenestration Ratings Council (aka: NFRC) – An industry association which sets standards for testing, rating, and labeling doors and windows with heat transmission and energy information.

Night Latch – A lever or knob-actuated bolt for fastening a window more securely at night which is generally offered on vinyl windows.

Non-Keyed Cylinder - A handle without a keyed cylinder. The door cannot be locked from the exterior.

Non-Removable Pin Hinge (aka: NRP) – A hinge with a non-removable pivot pin. NRP hinges are used when exterior doors swing out, as a security feature. The fixed pins make it impossible to remove a door by driving out pivot pins.

NWWDA – National Wood Window and Door Association. Trade organization that has established many standards related to wood window and door products. It is now the Window and Door Manufacturers Association (WDMA).

Obscure Glass – Glass formed by running molten glass through special rollers. These rollers have a pattern on them causing the glass to become patterned and thus obscure. This type of glass is commonly used in bathrooms.

Operation - The ventilating sash/panel of a unit. A unit is generally viewed from the exterior with X representing an operating sash/panel and O representing a stationary sash/panel.

Operator – A device for opening and closing windows. Usually refers to a crank-operated mechanism found on casement and awning windows.

OSM - Refers to an outside measurement of an opening.

OX - The letters OX or XO identify the operation of window or door units as viewed from the exterior. The letter O stands for stationary while the letter X stands for operating.

Outswing (aka: OS) – A term used to describe an exterior entry door unit for which, when the hinged door panel is opened, the panel swings out of the building. Commonly used in garage utility doors.

Palladian – A large, arch-top window flanked by smaller windows on each side.

Pane – A framed sheet of glass within a window or door.

Panel – Component, usually wood, mounted within stile and rail members of doors. It is also used to refer to the entire door.

Panning – In replacement window work, the outside aluminum trim that can extend around the perimeter of the window opening; which is done to cover up the old window material.

Parting Stop– A narrow strip that separates and secures two sash in a window frame of a double hung creating a channel in which the sash can move.

Passage Lock – A lockset which will retain a door closed, but which cannot be locked.

Passive – In a double door assembly, the door which remains closed and locked by bolts at top and bottom, and is used less frequent. To open the passive door, one would first have to open the active door.

Picture Window – A non-operating window.

Pitch - The degree of the inclination upward from horizontal or flat. It may be expressed in degrees or as the ratio of the number of inches it rises in each 12 inches of horizontal span; 4/12 means the roof rises four inches in every foot of horizontal span.

Plinth Block - A decorative wood block placed between the vertical casing and the top casing of a unit to provide and elegant interior casing profile.

Plumb – Vertically straight. As an installation term, it refers to the importance of making sure that the window sides are perfectly perpendicular to the earth.

Pole Crank - An aluminum extension pole used to open or close roof windows which would be inaccessible because of their height.

Polygon – A term used to describe window shapes without curves as in rectangles. Examples include: triangles, trapezoids, pentagons, hexagons and octagons.

Polyvinyl Chloride (aka: PVC) – Aplastic material used to make molded or extruded parts.

Prime - The first coat of paint in an application that consists of two or more coats; also refers to the paint used as initial coat (primer)

Pultrusion- Lineal profiles of constant cross section manufactured by combining plastic resin and continuous glass fiber reinforcement. These thermally insulation and structural components are ideally suited for applications where strength, thermal stability and weather resistance are required, such as in patio door frames and commercial windows.

Pyrolytic Low E Glass (aka: Hardcoat) - Pyrolytic Low-E is designed to be used either in non-insulating applications such as energy panels that have exposed surfaces or for insulating glass applications. In some northern climatic situations where an application or customer requires increased solar heat gain, over Low E II performance, this is a desirable option. This increased solar heat gain which is desirable in winter may increase summer energy costs of the home is air conditioned. The pyrolytic coating is typically applied to the second surface, but can be applied to the third surface to provide increased solar heat gain.

Rabbet - A groove along or near the edge of a piece of wood.

Radius - The length of an imaginary line from the center point of a circle to the arc or circumference of a circle.

Radius Window – This type of window features curved components. It may include full round, half-round, quarter-round, arch top, elliptical, and springline windows.

Rafter - Structural members of a roof that support the roof load and run from the ridge to the eaves (overhang).

Rail – Horizontal member of a window sash or door panel. There are four rails on a double-hung window: the bottom rail, two meeting rails or check rails, and the top rail.

Retro-Sizing - Refers to units which are sized for replacement purposes.

Reveal – That part of the edge of a door or window jamb not covered by the casing.

Reverse Cottage Window – A double hung window with unequal sash. The bottom sash is shorter than the top sash.

Riser –A term which describes the part of an adjustable sill which can be moved up or down by turning adjusting screws to meet the bottom of the door for an optimal seal.

Roll-form Cladding– Cladding that is not extruded aluminum. It is cut from a larger sheet of aluminum and is formed through a series of rollers.

Rosette- A circular cover plate attached to the stile directly behind a knob or door handle. May be plain or have a decorative design embossed into the cover.

Rough Opening (aka: RO) – The opening in a wall where a window or door will be installed. Openings are larger than the size of the unit to allow for insulation and to shim the unit square.

Rough Sill- The horizontal rough framing member, usually two inches by four inches, which forms the bottom of the rough opening. It is toe-nailed into the jack studs and is supported by cripples.

Round Top– Generally a semicircle window which is mulled to the top of another window or door, thus forming the round top appearance. There are full round tops, separated round tops, elliptical, transoms, inverted corners, ovals and Gothic heads, etc. Round tops can be used separately or combined with other units to create a seemingly endless selection.

R-Value – The resistance a material has to heat flow (loss or gain). Higher numbers indicate greater insulating capabilities.

Safety Glass (aka: Tempered) – Float glass panels heated and then cooled rapidly in a controlled environment. This process makes the glass several times stronger than regular glass. It also makes it safer because when broken it yields small pebble-like fragments.

Sash– The operating and/or stationary portion of the window unit that is separate from the frame. The sash consists of stiles (vertical sash members) and rails (horizontal sash members).

Sash Balance- A system of weights, cords and/or coiled springs which assist in raising double-hung sash and tend to keep the sash in any placed position by counterbalancing the weight of the sash.

Sash Cord – Rope or chain in double hung windows that attaches the sash to the counter balance.

Sash Lift – Protruding or recessed handle on the inside bottom rail of the lower sash on a double- or single-hung window.

Sash Lock– A cam-action type lock applied to the check rails of a sliding window or at the open edges of a projecting window to pull the check rails tightly together or to seal the sash tightly to the frame, both for security and weathertightness.

Sash Opening (aka: SO) - The opening between wood frame members for both height and width (disregarding and jamb hardware tracks).

Sash Width- Horizontal measurement across the face of a sash.

Sash Weights – Concealed cast-iron weights used to counter balance the sash of older double hung windows.

Screens - A close-mesh woven material of metal or fiberglass attached to an aluminum or wood surround. Screens inhibit entry of insects, yet permit light, air and vision. Screens are generally available as full and half.

Screen OM (outside measurement) - The width and the height of a screen including wood or metal surrounds.

Seal Failure – When the vacuum seal between 2 panes of glass in a window is lost and air gets into the cavity. Seal failed glass tends to have a “milky” appearance.

Seat board - A flat board cut to fit the contour of a bow or bay window and installed between the sills and the flat wall surface, providing a seat or shelf space.

Shim –A thin piece of material used between the window/door unit and the rough opening to support the unit, center it within the rough opening, and adjust it to a plumb, level and square position. If tapered shims are used, they must be used in pairs with the tapers opposing each other to avoid tilting the unit or twisting the jambs.

Side Jamb- The side (vertical) member of a frame.

Sidelite (aka: SL) –A stationary glass panel mulled next to a door, for decorative purposes. They almost always contain glass.

Sill – The horizontal member forming the bottom of a window or exterior door frame; the lowest member of the frame of a structure, resting on the foundation and supporting the frame.

Sill Course (soldier course) - The row of brick, cement blocks or stones laid across the bottom of a masonry opening which lay under the outside edge of the window sill.

Sill Horn- The extension of the lip of a window sill to the outside edge of the casing.

Simulated Divided Lite (aka: SDL) - Designed to mimic old-fashioned multipane windows. Grilles attached to the interior and/or exterior of a window, with or without a spacer bar between the glass to give the appearance of true divided lites.

Single Pane Glass- Glazing with a single piece of glass.

Single Hung– A window very similar to a double hung window, except that the top sash is stationary or non-operable.

Slide Bolt–The part of an astragal assembly which, by means of moving latches at tops and bottoms of astragals, places bolts into frame heads and sills, for fixing passive door panels closed.

Sliding Patio Door– A door fitted with two or more panels containing glass that move horizontally on a track.

Sliding French Door- A sliding door utilizing French door style panels.

Slope- The measure of the tilt of a line; rise over run.

Solar Gain– The process of providing a net heat gain within a structure, over and above the normal heat loss, by passive collection of the sun's heat through windows and other glazed areas.

Solar Heat Gain Coefficient (aka: SHGC) – A rating that measures a window’s ability to transmit solar heat. It measures both the solar radiation which is directly transmitted, as well as the solar radiation absorbed by the glass and subsequently transmitted. The lower a unit’s SHGC, the less solar heat it transmits, and the greater its’ shading ability.

Sole Plate- The bottom horizontal member in a frame wall. Usually either single or double 2”x4”s. It is nailed to the deck or rough floor and the studs are nailed into it.

Sound Transmission Class (aka: STC) – A rating measuring a window’s acoustic properties or its ability to reduce sound transmission. An STC rating is determined by measuring the sound transmission over a selected range of sound frequencies. The higher the number, the less sound transmitted.

Space Mull- Two or more units mulled together with a space left between the units. The jam extension surrounds the entire unit.

Spacer - Used to separate the two pieces of glass in an insulating glass panel.

Spacer Bar - Tiny aluminum bars inserted between SDL muntins to emulate ADL.

Sputter Coating – A secondary manufacturing process in which a thin layer of materials, usually designed to offer low-emissivity or solar-control benefits, is applied to glass.

Square Foot - For measuring the area of a unit. RO width (in inches) X RO height (in inches) divided by 144 equals the area in square feet of a unit.

Starburst - A semi-elliptical area, the lower center is the point where the dividing spokes meet and radiate outward. May be constructed of glazed sash, removable grilles, ADL or SDL.

Stationary - A non-operating sash, panel, or unit.

Stiles – The upright or vertical perimeter pieces of a sash, panel, or screen.

Stool – An interior horizontal trim member on a window which extends the sill and acts as a narrow shelf. Sometimes it is mistakenly referred to as a window sill.

Stop – A wood trim member nailed to the window frame to hold, position, or separate window parts. The stop is often moulded into the jamb liners on sliding windows.

Storm Sash– A framed assembly containing non-removable glass. The storm sash is generally removed during the summer and replaced with a screen.

Strike Plate– A metal plate attached to the door jamb, which receives the latch.

Structural Masonry Brackets - An installation bracket used with multiple high/wide window units or large doors for added structural support. The brackets are also used to attach the unit in the rough opening in lieu of nailing through the casing, thus eliminating unsightly nail holes.

Stud- Vertical wood framing members which for a frame wall. In normal construction these are eight foot-long 2”x4”s.

Stud Pocket - Two or more units mulled together with a space between the units. The jamb extension surrounds each unit separately, providing space for a support member between the units.

Sub-Floor – The concrete or wood floor surface lying under the finished floor.

Sub-Sill - The supplemental member of a frame used under most awning and casement units as an additional sill with the primary purpose being to home multiple units together at the sill.

Sunburst - A semi-elliptical area, the lower center of which contains a sun-like figure with sun rays radiating therefrom. May be constructed of glazed sash, removable grilles, ADL, or SDL.

Surround – On a grille, it is an attractive, protective trim which is secured to the perimeter to give stability. On a screen, it is the framework which holds the mesh and is usually made of aluminum.

Tempered Glass (aka: Safety Glass) – Float glass panels heated and then cooled rapidly in a controlled environment. This process makes the glass several times stronger than regular glass. It also makes it safer because when broken it yields small pebble-like fragments.

Template - A pattern of a window unit from which dimensions and measurements can be determined. Round tops sometimes require templates for replacement applications.

Tenon – A rectangular projection cut out of a piece of wood for insertion into a mortise.

Thermal Break – Part of a window or door that reduces transfer of cold or heat from one surface to another.

Threshold – The piece (wood, stone or other material) placed beneath a door to trim off the inside of the door sill.

Tilt Window – A single or double hung window whose operable sash can be tilted into a room to allow cleaning of the exterior surface from the inside of the building.

Transom– A window above a window or door. Transoms can be either stationary or operating.

TruScene® Insect Screen – A nearly invisible micro-fine stainless steel mesh insect screen that is one-third the diameter of a standard screen wire and allows over 50% more clarity than an Andersen conventional insect screen.

Ultraviolet Light (aka: UV) – Electromagnetic radiation with a wavelength shorter than that of visible light, but longer than x-rays and is so named because the spectrum consists of electromagnetic waves with frequencies higher than those that humans identify as the color violet. It is the invisible solar radiation that can cause heat buildup and fading of wood, fabrics and other surfaces. (Low-E coatings are added to window glazing to moderate or eliminate harmful undesired UV wavelengths of light.)

Ultrex® – A pultruded composite material made of polyester resin and glass fibers. This superior material is now being used in many Marvin products.

U-Value – A measure of total heat flow through a window or door barrier from room air to outside air. Lower numbers indicate greater insulating capabilities.

Vapor barrier - A watertight material used to prevent the passage of moisture into or through floors, walls, and ceilings.

Veneer – A thin sheath of wood usually applied over a stronger material creating a beautiful finish. Today, veneers are used over many types of materials including fiberglass, vinyl, and aluminum.

Venting Unit – Window or door unit that opens or operates.

Vinyl-Clad Window – A window with exterior wood parts covered with extruded vinyl.

Weather Stripping– A strip of resilient material designed to seal the sash and frame members in order to reduce air and water infiltration.

Weep Hole – A small opening in a window or sill member through which water may drain to the building exterior.

Wind Load – Force exerted on a surface by moving air.

Wire Glass- Glass with wire embedded into the glass when the glass is still in a molten state. This prevents the glass from falling out of the sash if it should break.

XO - The letters OX and XO identify the operation of window or door units as viewed from the exterior. The letter O stands for stationary while the letter X stands for operating.