The foot at the rear during any given point of footwork
LA
 (Film) Low angle.
La Belle
 French term for the final touch, when at sudden death in a normal bout. A clear touch.
La Canne
 19th century French stick fighting technique.
Lames
 Metal strips forming part of flexible armour.
Langets
 Small finger-like projections from the centre of the quillions flanking the blade.
Lateral parry
 See Simple parry.
Lead foot
 The foot at the front during any given point of footwork.
Left back ward
 Weapon held point back and to the left, close to the hip. Viggiani's fourth wide guard.
Left dominant
 Landing with the left foot forward.
Left hander
 Person who favours the left hand over the right. A fight notation nightmare, and there's always one.
Lineas Infinitas
 Imaginary lines on the floor that join the combatants' feet in Spanish rapier play.
Line
 a/ A specific area of the body which is threatened or covered from attack. b/ Imaginary planes that bisect the body, both vertical (Inside and outside lines) and horizontal (High and low lines.).
Line of engagement
 The area in which the blade is threatening attack.
Linea
 The lines of engagement.
Lines of attack (Lines)
 Imaginary horizontal and vertical lines splitting the body into high, low, inside and outside target areas.
Lock
 To jam or fix securely.
Locking nut
 Small nut screwed into the tang of modern fencing weapons.
Long sword
 A sword with a simple cross-hilt and long cut and thrust blade.
Loosing the sword
 Any disarm which removes the sword from the hand allowing it to fall freely to the stage.
Low Angle
 (Film) Camera looking up at the subject.
Low guard
 Generally, but not always the same as it's numbered correspondent, but with the sword hand in a lowered position, the arm often straightened and feet slightly further apart. 
Low invitation
 A stance in which the hand is too low to prevent any attempted attack, usually with the arm hanging loose from the shoulder, the point low. Good for resting when out of distance.
Low parry
 Generally identical to any numbered parry, standard or crossed, but slightly lower. As with the high parry this leaves some target area vulnerable to second intention attack. Most used parry of this type in my experience is the Low prime, which can cover virtually all of the left side of the body, if necessary. 
Low Parry of five
 This parry defends the groin from an rising cut, can throw you considerably off balance, and is often substituted for an evasion.
Low line
 The area of attack below the sword hand. The parts of the opponents target visible below the sword hand.
Lower side ring
 The larger of the two side rings found on the two-ring and swept-hilt rapier hilts, situated the closest to the weapons pommel. 
LS
 (Film) Long Shot.
Lunga
 Lunge.
Lunge
 Forward movement executed by advancing the leading foot forward while the rear foot remains stationary.  It is usually associated first with a straightening of the arm as the beginning of an attack.