The horse itself
Age, sex, breeding and height — the vocabulary for describing an individual horse.
Barrel
The body of the horse between the forelegs and the hindquarters — the part a cinch goes around and a rider's leg lies against.
Bloodline
A family within a breed, traced through a named ancestor. Half of western horse talk is really about six or seven of them.
Broodmare
A mare kept for breeding. A good one is judged on what her foals do, which takes most of a decade to find out.
Cannon bone
The long bone between knee or hock and fetlock. Nothing much but bone and tendon covers it, which is why leg boots exist.
Cob
A short-legged, thick-set, sensible sort of horse. In Britain a type and a size class more than a breed.
Colt
A male horse under four. Not a generic word for a young horse, though it gets used as one, and not a word for a young gelding either.
Conformation
How a horse is put together — angles, proportions, straightness. What a halter class judges, and what predicts what a horse can hold up to.
Croup
The top of the hindquarters, from the highest point behind the saddle back to the tail.
Dam
A horse's mother. A pedigree is read sire on the top line and dam on the bottom, and the bottom half is the half people skip.
Fetlock
The joint just above the hoof, with the tuft of hair behind it. It flexes far more than a photograph suggests.
Filly
A female horse under four. She becomes a mare at four, whether or not she has ever had a foal.
Foal
A horse in its first year, of either sex, usually still with its mother for the first months of it.
Forehand
The front half of the horse — shoulders, forelegs, neck and head. A horse on its forehand is carrying too much weight there.
Gaskin
The muscled part of the hind leg between stifle and hock. A quarter horse's is the reason the breed looks the way it does from behind.
Gelding
A castrated male horse. The default riding horse almost everywhere, because the job is easier without the hormones.
Gestation
How long a mare carries a foal — around eleven months, with a fortnight either side being entirely normal.
Get
The offspring of a stallion, taken together. A sire's get is what his reputation is actually made of.
Grade horse
A horse with no registration papers, whatever its parents were. Sold on what it can do rather than what it is written down as.
Hand
The unit a horse's height is given in, four inches, measured to the withers. Written 15.2, meaning fifteen hands and two inches — not fifteen and a fifth.
Hindquarters
The back half of the horse, and the engine. Nearly every training complaint traces back to it not being used.
Hock
The big joint halfway up a hind leg, pointing backwards. It is the horse's equivalent of an ankle, and it takes the load in a stop.
In foal
Pregnant. A mare sold in foal is being sold as two horses, at whatever risk that carries.
Linebreeding
Breeding back towards one admired ancestor so it appears more than once in the pedigree. Inbreeding with a target and a limit.
Mare
A female horse four years old or more. Younger than that and she is a filly.
Outcross
A mating between two horses with no close ancestors in common — often used to bring something back that a closely bred line has lost.
Papers
A horse's registration certificate. "Papered" means the registry recognises the pedigree; it says nothing about how the horse rides.
Pastern
The short sloping section between fetlock and hoof. Its angle and length change how much concussion the leg absorbs.
Pedigree
The written record of a horse's ancestors, sire's line along the top and dam's along the bottom, going back as many generations as the registry holds.
Poll
The top of the head just behind the ears. What people mean by a horse being soft or stiff at the poll.
Pony
A horse under 14.2 hands, by most registries' definition. A height class rather than an age, and not a young horse.
Produce
The offspring of a mare, taken together. The mare's side of the same idea the word get covers on the stallion's.
Progeny
Offspring of either parent, and the neutral word sale catalogues use when they mean get or produce without saying which.
Purebred
A horse whose parents are both registered in the same breed registry. A breed is a set of records as much as a set of horses.
Registry · stud book
The body that records a breed's pedigrees and issues papers, and decides what counts as the breed at all.
Sire
A horse's father. Used as a verb too: a stallion sires a foal, and the foals collectively are his get.
Stallion
An uncastrated male horse four or over. Kept as one only where there is a reason to breed from him, and handled accordingly.
Stifle
The joint high on the hind leg, roughly where a human knee sits, mostly hidden by the muscle around it.
Topline
The outline along the neck, back and croup. Muscle that appears or disappears there is the quickest read on how a horse is being worked.
Warmblood
A sport-horse type bred from heavier stock crossed towards thoroughbred, registered by studbooks that select on performance rather than ancestry alone.
Weanling
A foal that has been separated from its dam and is no longer nursing, typically from around six months old.
Withers
The ridge where the neck meets the back, between the shoulder blades. Height is measured to it, and saddle fit starts there.
Yearling
A horse in its second year. Old enough to be sold, shown in hand and prepared, and too young to be ridden.