Cannon (or cannon bone):  The metacarpus or the metatarsus.  So-called because of its similarity in shape to the barrel of a cannon.  Since "cannon" might be construed as meaning only the unfleshed cannon bone, the term "shank" was suggested by Professor J. C. Ewart as a more inclusive name.  Among horsemen, however, "cannon" is taken to mean the whole metacarpal or metatarsal segment.  It is at the level of the slenderest part of the cannon that the "girth of cannon," commonly called "bone," measurement of a horse is taken.

Canter:  One of the four gaits of a horse.  Walk, trot, canter, then gallop.  Follows the same sequence as the gallop but the cadence is slower and the hind legs do not propel the horse as strongly as in the gallop.  It is a rhythmic and collected gait for pleasure riding.  Canter is a three-beat gait, usually smooth and easy to ride.  (Also the term for a working-out gallop.)

Cast or Draw a covert:  In hunting, to search for the scent, hounds casting on their own or directed by the huntsman.

Cry or Give Tongue:  In hunting, the baying of a fox hound.

Charger:  One of the more familiar terms for a war horse, as distinguished in the Middle Ages from the palfrey.

Cheeks:  The part connecting head and neck, between the rear edge of the lower jaw-bone and the atlas.

Chestnut:  A color term for a plain red horse.  Also, the horny growth on the inside of the foreleg slightly above the knee, or on the inside hind leg just below the hock.  The latter were presumably named for their resemblance, real or imagined, to a chestnut, and are also called castors.

China or wall-eye:  Pale blue or pale brown eye in which there is very little or no pigment in the iris, giving it a somewhat glassy appearance.  Albino characteristic.

Clydesdale:  One of America's most popular draft (working) horses.  Clydesdales are huge (18 hands or more), powerful work horses used for hauling heavy carts or farm machinery.  They are usually bay or black in color, with "feather" (long hair) covering their hooves.

Cob:  Short, stocky horse (not more than 15.3 hands).  Quiet and well-behaved.  (Another source has specified that this name applies to a "strong, thickset, short-legged horse of medium size" -- the latter of which it defines as 13.2 to 15 hands high.)

Coffin bone:  The foot bone, or third phalanx, enclosed within the hoof.  If we consider the hoof as a "coffin," or receptacle, the term is self-descriptive.

Cold-blood; cart horse; heavy horse:  These terms are synonymous.  Cold-blood horses are usually very carefully bred; most trace their ancestry back to the Great Horses of the Middle Ages, which in turn are descended (though many thousands of generations removed) from the diluvial or forest horse (Equus przewalskii sylvaticus).  Embraces all heavy draught horses with the corresponding breed features, heavy build, large massive head, short, thick neck, often with double mane, cleft croup, tail carried low, short stocky limbs of great strength in the bone, feathers.

Colic:  A term used to describe stomachache in horses.  Colic can be deadly serious or simply a bout of gas that passes on its own.

Colt:  A young male horse, up to three years old (or whatever age is considered "adult," sometimes four or five).  Incidentally, the term may also be applied to young male donkey, a zebra, or a camel.

Conformation:  Physical characteristics and structure of the horse.

Constricted hoof:  Hoof where expansion is limited.

Contracted heel:  Contracted walls of the hoof affecting the motor muscles of the foot.

Coronet:  The comparatively soft lower portion of the pastern where the skin joins the hoof.  The term, meaning "small or inferior crown," has been here applied presumably because of the location and form of the upper margin of the horse's hoff.

Cow-hocked:  Toes of rear leg placed wide apart.

Cow sense:  Special talent for working with cattle.

Cross:  A mating between horses of two different breeds, or of different family lines within a breed.

Crossbred:  A mating between horses of any two different breeds except the Thoroughbred.

Croup:  The place behind the saddle.  Specifically, the posterior part of the back between the loins in front and the tail behind, extending sidewards the width of the pelvis.  From the French croupe, meaning rump or buttocks.

Curry comb:  A hard rubber brush used to remove deep or caked-on dirt or mud.  It should be used vigorously but carefully, because it is hard.  It is not used on the lower part of the legs, nor on the face.  Once the dirt has been brought to the surface and loosened, it can be brushed away by the softer bristled body brush.  Also used for cleaning the body brush.