1. A material added to a building material such as mortar or plaster to retard or accelerate the set. 2.

An opening in a wall, with a door, which provides a passageway into a room or building.

1. A door and frame assembly. 2. As specified in building codes: the clear opening of each door in a

The casing or moldings used around a doorframe to conceal the crack or joint between the frame and wall or

The jamb or sidepiece of a door.