Labelled Door (or Frame) A door or frame that conforms to all the applicable requirements, in respect to fire resistance, of a nationally recognized testing authority and bears a label designating that fire rating.
Laminate The process of or a product made by, bonding together two or more layers of material or materials.
Landing A stair platform.
Latch A door fastening device having no locking function.
Latchbolt A spring-actuated, bevelled bolt usually operated by door furniture.
Latchset A door fastening mechanism, comprising of latch, strike and door furniture.
Lateral Movement Movement toward the side, sideways.
Lead-Lining The lining of a door, frame or lock with sheet lead. Primarily used in hospitals or other areas where there is a potential radiation hazard. May also be used for soundproofing.
Leaf a) Hinge – One of the two movable plates which, when fastened together by the hinge pin, form a complete hinge. b) Of a pair of doors – one of the two doors forming a pair of a double door.
Legal Measures Patent protection or design registration.
Lever See Tumbler.
Lever Handle A bar for operating the latchbolt of a lock.
Lever Lock A lock operated by a lever mechanism.
Lift Off Hinge See Hinge.
Lip of Strike The projecting part of the strike on which the latchbolt rides. It may be either a curved lip or flat lip.
Lock A fastening device activated by a key and/or turnknob and/or electricity
Lock Rail (of a door) The horizontal member of a door that houses the locking mechanism.
Lockset A lock, complete with strike and door furniture, such as knobs, levers, escutcheons, or handles.
Lock Stile (of a door) The vertical member of a door in which the lock is housed, as distinguished from the hinge stile.
Loose Pin Hinge See Hinge.
Louvre A ventilating window covered by sloping slats to exclude rain or light.
Lubricity The property of slipperiness, oiliness, smoothness.