Home remodeling projects can be downright daunting. You have a beautiful vision for your project but secretly dread the steep learning curve you'll have to climb to get there.

Not only do you have to build an understanding of how the elements of the project work together from a system's perspective, but it's critical for you to understand what each element in the system is in the first place.

One of the best home remodeling pro tips we can offer you is to brush up on your industry vocabulary before you embark on your ambitious project. You'll open up the doors to more productive conversation with other home remodeling professionals and cultivate a heightened understanding of your own project. So next time you stall out on that hilly learning curve, use this glossary of window and door terms to get you back on track.

Air infiltration - an industry test that measures the amount of air leakage through a window or door (often used to inform energy efficiency compliance).

Apron - the decorative trim that sits underneath a window stool.

Argon - the gas used in between insulating glass panes to reduce heat transfer.

Astragal - the middle post of a double door attached to the fixed door frame.

Awning Window- a window with an outward swining sash from the bottom.

Bay Window - a group of three windows (one in the center with two anlged flanking units) that form a protruding window system.

Bow Window - a group of four or more windows that form a similar system to the bay windows for the same effect.

Bottom Rail - lowest horizontal member of the framework of a window sash or door.

Brick Mould - an external casing for windows and doors.

Casement Window - a window with one or more sashes that swing out to the right or left as opposed to sliding up and down.

Casing - the decorative molding seen on the interior edges of a window or door. An easy way to remember this term is to imagine the window being enclosed in a case.

Cladding - the protective coating attached to the exterior of a window or door to protect it from the elements.

Caulking - a compound substance used to seal cracks and plug small points of air or water leakage. 

Clerestory - a window located at a high, unreachable place on the wall.

Combination door/window - a screen or storm door/window used in concert with a primary door/window. 

Cornice - the ornate molding at the top of an exterior trim.

Double-hung - a window where the upper and lower sash sit in a single frame and slide vertically past one another.

Dowel joint - a corner joint created by boring matching holes into a door rail and style using a dowel pin to conjoin the two.

Egress window - a window large enough to be used as an emergency exit.

ENERGY STAR® - A government run program that helps consumers identify energy efficient products, upgrades, and practices.

Extension jamb - A board or trim component that extends from the interior of the window frame to the interior wall. It's used to increase the depth of the jambs of a window to fit a wall of any given thickness.

Fanlight - A half-circle window over a door or window.

Flashing -  Water repellent material that directs water away from your windows.

Finger-joint - toothed joint used to combine two pieces of wood end-to-end.

Frame - Outer structure of a window or door that holds the sash or panel in position.

French door - Hinged door(s) with glass areas surrounded by a wide wood side stiles and a tall bottom rail

Glazing - this one isn't as intuitive as a lot of these terms but is certainly more simple than most of them. Glazing refers to the glass in a window sash or door panel; the act of installing glass in a window sash or door panel

Glazing bead - the wood or vinyl pieces around the perimeter of the glass that bridge the space between the glass edge and sash/panel.

Handing - the direction that hinging windows and doors open in which is determined by hinge placement.

Insect screen - a woven wire mesh attached to a frame which allows air ventilation while simultaneously keeping insects out.

Insert window - a new window installed into an existing frame pocket.

Jamb - a side post or surface of a doorway, window, or fireplace.

Jambliner - the track installed inside the jambs of a double-hung window. This is how the sashes can vertically slide.

Lift - the handle on the bottom of a double hung window that can be used to raise or lower the window sashes.

Lintel -  a beam situated above a window or door opening that supports the wall above. 

Meeting Rail -  also referred to as the 'Check Rail', this is the middle horizontal member of the framework of a window where the top and bottom sashes meet and where the locking mechanism is mounted.

Mullion - the horizontal or vertical joints that separate smaller, individual window or door units.

Mulling - the process of joining two or more window or door units together.

Panel - the combination of the rail, stile and glass on a window or door.

Performance Grade (PG) - An industry rating for a unit that has been tested for air, water, structural and force entry performance. Used to determine compliance with code required design pressures.

Pre-finished - a unit that is ready for installation.

Rail - the horizontal component of a window sash or door panel framework 

Rough Opening - the opening in a wall prior to the installation of the window or door. The rough opening should be larger than the actual unit to allow for insulating and adjusting unit placement.

Sash - this is not a long strip of cloth you wrap around your waist. Rather, this is the component of the window that you can lift up and down to let air in or out of a space. Typically there is a top and bottom sash which are comprised of rails, glass, and stiles. 

Sash stiffener - a reinforcement designed to increase the strength of the unit.

Seal - a pliant compound that inhibits air and water passage.

Shim - a wedge used to level a window or door in the rough opening.

Sill - the horizontal bar that forms the bottom of a window or door frame.

Stile - the vertical side paneling components of windows and doors (the counterpart to the rails).

Stool - an interior trim piece sometimes used to extend a window sill and perform as a narrow shelving unit.

Stop - a trim element attached to the window or door intended to hold, position or separate components.

Sun glass - tinted glass that reduces heat transfer.

Tensile Strength - the measurement of force required to push a material past its breaking point. 

ProEdge Remodeling's Point 1 storm windows are constructed with a tensile strength that's a whole level above the industry standard. This provides added protection from forcible wind, weather, and even helps dampen noise.

Transition Block - a decorative wood piece used to cover the joint between extension jambs or casings.

Transom: a window placed directly above another window or door.

Top Rail - uppermost horizontal member of the framework of a window sash or door.

U-Factor - a measurement of heat transmission through a window/door. 

Weatherstripping - compressible material designed to seal the sash or panel to the frame.


Did we miss a term that you need defined? You can reach us in the comments section. Feel free to share terms that should be included in our list or share some home remodeling pro tips of your own!