Labrador Retriever: A breed of dog originating in Newfoundland, having a short, yellow, black, or brown coat and a tapering tail and used in hunting to retrieve felled game.

Lactation: Secretion or formation of milk by the mammary glands.

Lame: Irregularity or impairment of locomotion.

Landseer: Newfoundlands that are white dogs with black markings, named in honor of Sir Edward Landseer, the 19th Century artist who used these dogs as models

Lateral: Pertaining to the side.

Layback: The angle of the shoulder blade as compared with the vertical plane viewed from the side.

Layon: The angle of the shoulder blade as compared with the vertical plane viewed from the front.

Lead: A strap, cord, or chain attached to the collar or harness, or sometimes simply around the neck, for the purpose of restraining or leading the dog. Also called leash.

Leash: A chain, rope, or strap attached to the collar or harness of an animal, especially a dog, and used to lead it or hold it in check.

Leather: The flap of the ear; the outer ear supported by cartilage and surrounding tissue.

Lemon: Used to describe pointers, this color is a brilliant, medium-saturated yellow. Color definitions may vary by breed. Always check the breed standard for the definitive color description.

Leptospirosis: An infectious disease of domestic animals, especially cattle, swine, and dogs, caused by spirochetes of the genus Leptospira and characterized by jaundice and fever.

Level Bite: When the front teeth (incisors) of the upper and lower jaws meet exactly edge to edge. Also called pincer bite, equal bite, or even bite.

Level Gait: Dog moves without rise or fall of withers.

Lhasa Apso: A breed of small dog originating in Tibet and having a long, straight coat.