Window & Door Glossary
Doors & Windows and Hardware Glossary
Understand key window, door and hardware terms for your next Hotian project.
Hotian specializes in international doors and windows solutions. This comprehensive
glossary helps you quickly understand the terminology used across our website, product catalogs, and quotations.
Door Types & Parts
A primary exterior door that provides the main access into a home or building, designed to combine security, durability and curb appeal.
Interior Door
A door used inside the building to separate rooms or spaces, where sound control and style are more important than weather resistance.
Any door installed on the outside wall of a building, typically built with enhanced insulation, weather sealing and security hardware.
A pair of doors with large glass areas that open from the center, often used to connect indoor living spaces to a patio, balcony or garden.
A patio door where one or more panels glide horizontally along a track, saving interior space and maximizing glass area.
A multi-panel door system where panels fold and stack neatly to one or both sides, creating a very wide clear opening to outdoor spaces.
A door that slides along an exposed track mounted on the wall above the opening, often used as a decorative interior feature.
Commercial Door
A door system designed for shops, offices or public buildings with higher traffic, stricter safety codes and heavy-duty hardware.
A door made primarily from natural wood components, valued for its warmth and premium appearance.
A door constructed with aluminum profiles, offering slim sightlines, durability and low maintenance for modern residential or commercial projects.
A door made from unplasticized PVC profiles, commonly used for energy-efficient and low-maintenance exterior doors in many markets.
A door with a steel skin or structure, typically chosen for entry applications where security, fire rating and durability are critical.
Door Slab / Door Panel
The door leaf itself without the surrounding frame, hinges or hardware.
Door Frame
The structure built into the wall opening that supports and surrounds the door panel or panels.
Head / Head Jamb
The top horizontal member of a door or window frame.
Jamb / Side Jamb
The vertical sides of the door or window frame.
Hinge Jamb
The jamb where the hinges are mounted.
Strike Jamb / Lock Jamb
The jamb where the latch or bolt engages into the strike plate.
Sill / Threshold
The bottom horizontal part of the frame that you step over, designed to support the door and help seal out water and air.
Stop / Door Stop
The raised strip on the frame that the door closes against.
Astragal
The vertical member between a pair of doors that helps seal the gap where they meet.
Window Types & Parts
A window hinged at the side that swings outward or inward, usually operated by a handle or crank, offering excellent ventilation and tight sealing.
A window hinged at the top that opens outward from the bottom, allowing ventilation even in light rain.
A window where one or more sashes slide horizontally along a track within the frame, ideal for wide openings.
A window with a fixed upper sash and a lower sash that moves vertically, a traditional style in many markets.
Double-Hung Window
A window where both upper and lower sashes can move vertically, allowing flexible ventilation and easy cleaning.
A large fixed window that does not open, designed to frame outdoor views and maximize natural light.
Window Wall
A floor-to-ceiling or large-span window system that creates a mostly glass exterior wall for expansive views and daylight.
Tilt-Turn Window
A European-style window that can tilt inward at the top for ventilation or swing in like a casement for full opening.
Tilt-and-Slide Door / Window
A unit that tilts inward for ventilation and also slides along a track to open wider.
A window with frames and sashes made from unplasticized PVC, known for energy efficiency and low maintenance.
Aluminum Window
A window built with aluminum frames, offering slim profiles and strength for modern designs and large openings.
Frame
The fixed outer structure that surrounds and supports the window or door unit in the wall opening.
Sash / Panel
The operable or fixed part that holds the glass in a window (sash) or a door (panel).
Mullion
A vertical or horizontal structural member that joins two or more window or door units together.
Door & Window Operation
Active Panel
The primary operating door panel in a pair or multi-panel system.
Inactive Panel / Fixed Panel
The panel that normally stays locked in place and is only opened when a wider clear opening is needed.
Inswing Door
A door whose active panel swings into the interior space when opened.
Outswing Door
A door whose active panel swings toward the exterior when opened.
Gliding / Sliding Door
A door whose panels move horizontally along a track instead of swinging.
Bypass Door
Sliding doors that pass each other on parallel tracks, commonly used for closets or wardrobes.
Hardware & Locking
Hinge
A hardware component that attaches a door or window sash to the frame and allows it to swing open and closed.
Handle / Operator
The part used to operate a window or door, such as a lever handle on a door or a crank handle on a casement window.
Lockset / Door Lock
A complete locking assembly for a door, typically including the latch, deadbolt and handle or knob.
Multi-Point Lock
A locking system that secures the door or window at several points along the frame with a single handle operation, improving security and weather performance.
Latch
A spring-loaded bolt that keeps a door closed but not fully locked, usually engaged by the handle.
Deadbolt
A solid bolt that is extended and retracted by a key or thumb-turn to provide additional security.
Strike / Strike Plate
The metal plate on the frame that the latch or deadbolt enters into.
Flush Bolt / Surface Bolt
A bolt used on inactive doors to lock the panel into the frame at the head and sill.
Foot Lock
An auxiliary lock mounted near the bottom of a sliding door to secure the operating panel to the sill.
Lock Cylinder
The key-operated part of a lock that activates the latch or deadbolt.
Non-Keyed Cylinder / Dummy Trim
A handle or trim without a keyed cylinder, used where no exterior locking is needed.
Espagnolette / Tie Bar
A rod-driven mechanism that operates multiple locking points from one handle.
Friction Hinge / Friction Stay
A hinge for casement or awning units that holds the sash at a chosen open angle.
Limit Device / Restrictor
Hardware that limits how far a sash or door can open, often for safety.
Track / Rail
The guided channel along which a sliding door or window panel moves.
Threshold / Sill
The bottom part of a door or window frame that you step over, designed to support the unit and help keep out water and air.
Weatherstripping
Resilient strips used around sashes or doors to reduce air and water infiltration.
Glass, Spacer & Gas
Double Glazing / Double-Pane
An insulating glass unit made of two panes of glass with an air or gas space between.
Triple Glazing / Triple-Pane
An IGU with three panes and two air or gas spaces for enhanced energy performance.
Low-E Glass
Glass with a special coating that reflects heat while letting in light, helping keep interiors warmer in winter and cooler in summer.
Insulating Glass Unit (IGU)
A sealed unit made of two or more panes of glass separated by a spacer and air or gas, used to improve insulation and sound control.
Tempered / Safety Glass
Heat-treated glass that is stronger than standard glass and breaks into small, less sharp pieces for safety.
Laminated Glass
Glass made of two or more layers bonded with an interlayer, which holds fragments together when broken and improves sound reduction.
Tinted Glass
Glass with color added to reduce glare and solar heat gain.
Reflective Glass
Glass with a reflective coating to control solar heat and privacy.
Spacer Bar / Spacer
The component that separates the panes in an IGU and creates the sealed cavity.
Warm-Edge Spacer
A spacer made from low-conductivity materials to reduce heat loss and condensation at the edge of the glass.
Argon Gas Fill
An inert gas used between glass panes to improve insulation.
Krypton Gas Fill
A denser gas than argon, used in some high-performance IGUs for better insulation in narrow cavities.
Energy & Performance
U-Factor / U-Value
A measure of how much heat flows through a window or door; lower numbers mean better insulation and energy efficiency.
R-Value
The measure of resistance to heat flow; for windows and doors, it is the inverse of U-factor.
SHGC (Solar Heat Gain Coefficient)
The fraction of solar energy that passes through the glass; lower values reduce unwanted heat gain in hot climates.
Visible Transmittance (VT)
The amount of visible light that passes through the glass, affecting how bright the interior feels.
Air Leakage (AL)
A rating that shows how much air passes through a window or door at a given pressure difference.
Condensation Resistance (CR)
An index indicating how well a product resists condensation forming on the interior surface.
Sound Transmission Class (STC)
A rating that indicates how well a building element reduces airborne sound.
Impact-Rated / Hurricane-Rated
Products tested to withstand wind-borne debris and high wind pressures in severe weather zones.
Fire-Rated Door / Fire Door Assembly
A door, frame and hardware set tested to provide a specified level of fire resistance.
Energy Star® Certified
A product that meets regional energy performance criteria established by the Energy Star program.
Frame, Cladding & Materials
Cladding
The exterior facing material on a frame or sash, such as aluminum cladding on a wood core.
Composite Frame
A frame made from a combination of materials, for example wood and polymer or fiberglass.
Thermal Break / Thermally Broken Frame
A frame construction with an insulating barrier between interior and exterior metals to reduce heat transfer.
Frame Profile / Section
The shape and dimensions of the frame or sash cross-section, affecting strength, insulation and appearance.
Skin
The outer face material of a door panel, such as steel or fiberglass.
Core
The inner material of a door panel that provides strength, insulation and sound control.
Muntins, Grids & Aesthetics
Muntin / Grid / Grill
Bars that divide the glass area into smaller panes or create the appearance of divided lites.
Simulated Divided Lites (SDL)
Grilles applied to the surface of a single glass unit to mimic the look of traditional divided panes.
True Divided Lites (TDL)
A traditional construction where each glass pane is individually glazed within separate muntins.
Lite / Light
An individual pane of glass in a window or door.
Flashing, Sealing & Installation
Rough Opening
The structural wall opening into which the window or door is installed, usually slightly larger than the frame size.
Clear Opening / Egress Opening
The actual usable opening when the window or door is fully open, often subject to building code requirements for emergency escape.
Shim / Packing
Small blocks or wedges used to plumb, level and square a window or door during installation.
Flashing
Waterproof material installed around the perimeter of windows and doors to help direct water away from the wall system.
Weep Hole
A small opening in the frame or sill that allows water to drain out of the system to the exterior.
Nailing Fin / Mounting Flange
A thin flange around the frame used to fasten new-construction windows or doors to the wall sheathing.
Drip Cap
A molding or flashing above a window or door that helps divert water away from the unit.
Backer Rod
A compressible material placed in gaps before applying sealant to control the depth and shape of the sealant joint.
Sealant / Caulk Joint
The flexible material applied at the perimeter to create a weather-tight seal between frame and wall.
Drainage Path / Drainage Channel
Internal passages that direct collected water toward weep holes.
Industry Abbreviations
NFRC
National Fenestration Rating Council, an organization that provides standardized energy-performance ratings for windows and doors.
WDMA
Window and Door Manufacturers Association, a trade association that sets certain industry standards and guidelines.
AGWA
Australian Glass and Window Association, an example of a national window and glass industry body.
ASTM
A standards organization whose test methods are often used for structural, air, water and impact testing of fenestration products.
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