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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.