Laminitis: Condition, caused by systemic upset, in which the laminae inside the hoof become inflammed and painful to the horse. Severe conditions can lead to founder.
Lampas: Swelling of the hard palate in a horse's mouth. Sometimes seen in young horses as they transition to hard feed and grain.
Lateral Cartilages: Wings of cartilage attached to the coffin bone, within the foot.
Laryngeal Hemiplegia: Partial paralysis of the larynx causing difficulty in breathing and a characteristic noise, known as roaring as the horse breathes.
Lead: Term used to indicate the horse's leading leg in canter i.e. "right lead canter" or "left lead canter".
Leader: Either of the two leading horses in a team of four, or a single horse harnessed in front of one or more horses. The "near" leader is the left hand horse and the "off" leader is the right hand horse.
Leg Up: Method of mounting in which an assistant stands behind the rider and supports the lower part of his left leg and giving a boost as necessary as the rider springs up off the ground.
Levade: A classical air above the ground in which the forehand is lifted with bent forelegs on deeply bent hind legs -- a controlled half-rear.
Light Horse: Horse, other than a heavy horse or pony, which is suitable for riding or carriage work.
Light of Bone: Insufficient bone below the knee to support the horse and rider's body weight without strain. Conformation fault.
Line-breeding: The mating of horses having a common ancestor some generations removed, to accentuate particular traits or characteristics.
Lippizan/Lippizaner: Elegant breed of horse from Europe. Most famous for their performances in the Spanish Riding School in Austria.
Livery Stable: English term for boarding stable.
Loins: The weakest part of the horses back, lying either side of the vertebrae, just behind the saddle.
Lope: Slow western canter.
Longe or Lunge: The act of training a horse by working it in the various paces on a circle using a long longe or lunge rein. This rein is attached to the cavesson. Also novice riders may have their first lessons on the lunge as they learn the basics of position, without having to concern themselves with the control of the horse.
Lusitano: Portugese name for Andalusian horses.
Lymphangitis: Condition in which the lymphatic system, usually in the hind legs, becomes swollen and painful. Seen in working horses on full feed that have to be confined to their stall for some reason, such as severe weather or illness.