Glossary - H

A Glossary of window terminology

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Header

A horizontal framing member placed over the rough opening of a window or door to prevent the weight of wall or roof from resting on the window frame.  

Hopper Window

A window unit in which the top of the sash swings inward. 

Handing
A term describing the swinging direction of a window or door. Window or door hardware may also be left or right-handed.  

Hardboard
A board material manufactured of wood fiber, refined to form a panel. Hardboard has a density range of approximately 50 to 80 pounds per cubic foot. Created under carefully controlled combinations of pressure, heat and moisture hardboard has a characteristic, natural ligneous bond.  

Hardwood
One of the botanical groups of trees that has broad leaves in contrast to the needle-like leaves of conifers or softwoods. Hardwoods are usually deciduous, shedding their leaves in the fall or at the end of each growing season.  

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

Header Track
The track in the head jamb of a sliding/gliding window or door that guides the sash/panel as it opens and closes.  

Hinge
A jointed or flexible device on which a door or window turns. The earliest known hinges were T-shaped devices called strap or cross-garnet hinges. They were made of wrought iron with a crossbar fixed vertically to the door frame, and attached with nails to the door. In the 18th century, hinges for interior doors were H-shaped or L-shaped, and attached to the door with nails.  

Hinge Track
The part of a bar hinge that allows the pivot point of an awning or casement sash to slide as the window opens and closes.  

Hollow Core Flush Door
A flush door with a core assembly of strips or other units of wood, wood derivative or insulation board, that supports the outer faces and has intervening hollow cells or spaces.  

Horizontal Sliding Window
Two or more sash that slide horizontally past each other; one or more of the sash may be fixed or inoperative or all the sash may operate; in a closed position, the sash come together to form a vertical meeting rail.  

Hygrometer
An instrument that measures relative humidity in the air.  

Hygroscopic
Readily taking up and retaining moisture.