Glossary - C

A Glossary of window terminology

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Casing

Exposed molding or framing around a window or door, on either the inside or outside, to cover the space between the window frame or jamb and the wall. 

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. Also known as Round Top or Half Round. 

Clerestory window

A venting or fixed window above other windows or doors on an upper outside wall of a room. 

Cottage double-hung

A double-hung window in which the upper sash is shorter than the lower sash.

Cam-action lock and keeper
The mechanisms, which pull and secure the sashes together when placed in the locked position. A single-point locking mechanism that uses a “cam” action to lock and to pull the window sash against the frame forming a tight weather seal; large windows may have more than one cam lock.

Channel
The area of the accessory trim or corner post where siding or soffit panels are inserted. Channels also refer to the trim itself, and are named for the letters of the alphabet they resemble (e.g., J-channel, F-channel, etc.).

ClarityOne Glass
A chemical treatment that when applied to glass, helps to create a smoother surface that won’t attract or hold dirt and dust. Established by PPG Industries.

ClimaTech®
The brand name for the insulated glass unit that is present in Alside’s insulating glass packages. A ClimaTech unit will contain either two or three panes of glass, with one or two of those panes being a Low E surface. It will utilize the SST warm edge spacer system and contain either argon or krypton gas.

Course
A row of panels, one panel wide, running the length of the house from one side to the other, or, in the case of vertical siding, from top to bottom.

Coved glazing beads
A contoured piece of vinyl that holds the glass in place within the sash and adds an elegant, finished look.

Cam Pivot (also known as “pivot pin” or “torx pin”)
The pins on the bottom corners of single and double-hung sash that engage the balance and also allow the sash to “pivot” for easy removal and reinstallation.  

Capital
A capital marks the termination of a column and the beginning of a horizontal support of a beam or lintel. 

Casement Window
A window that opens from the side like a door. Historically, casements were the first working windows. They were strategically placed throughout a house to capture breezes and direct them through the rooms. Screens are hung internally to prevent bugs and dirt from entering the house.  

Casing
Trim around door and window openings, can be internal or external.

Checkrail
In a double-hung window, this is the bottom rail of the upper sash (upper checkrail) and the upper rail of the lower sash, where the lock is mounted (lower checkrail). It is also known as a meeting rail. 

Cladding
Aluminum or vinyl material attached to the outside of a window or door, which creates a more durable, low-maintenance product. Cladding can be factory-applied in many colors and does not require painting.  

Clutch
A part of the balance system into which the cam pivot is inserted or engaged.  

Combination Door
A door that is made with a wood panel in the bottom half and a screen for ventilation in the top half. Also called a ventilating door.  

Composite
A windows/door manufactured from a material other than solid wood or plywood.  

Concealed Lock
A locking system that has multiple locking points with the system’s mechanism hidden behind the side screen stops; the locking points engage into keepers located on the sash.  

Condensation
Condensation occurs when excess humidity in warmer air is released in the form of water droplets onto a colder surface such as a pane of glass.  

Core
The center of plywood or crossbanded construction; it may consist of lumber (solid or glued), particle board or veneer. Also core unit; innermost layer in veneered door construction.  

Corner Key
A mechanical fastener that aligns two pieces at a corner.  

Countersink
To enlarge the rim of the screw hole so the screw head can be inserted flush with the surface.  

Cove and Bead
A moulding profile that is concave with a sharp angle notched in the center; also called cove with a bead; used as glass bead or stop.  

Crossbuck
The panels of a door separated by intersecting diagonal rails and so arranged to simulate a sawhorse, especially one with the legs projecting above the cross bar; an arrangement of panels similar to the Roman numeral X; also sawbuck.  

Crowning
The bowing of a sill such that the center portion rises above both ends.