A door jamb is the vertical component of the frame of a door, on either side, to which the door is attached or secured. The word ‘jamb’ comes from the French term meaning leg. In a doorway, the door jamb comprises the two ‘legs’ of the door frame.
How a Door Jamb Can Be Used
Hinges are attached to the door jamb. Deadbolt plates also are attached to the door jamb and the deadbolt itself extends into the door jamb in order to secure the door. In closets, electrical triggers are sometimes installed on the surface of the door jamb or recessed slightly into the door jamb.
This allows the homeowner to have a ‘switch’ installed onto the door jamb which automatically turns on or off the light as you open or close the door. This is the kind of device that is something like the button which turns on or off the light found inside a refrigerator.