Hack

(noun) a horse for hire, or adapted to general work, used for driving or riding. Although the word sometimes means an old, worn out horse, it is also used to signify an extremely elegant horse used for riding on social occasions ("park hack", "hunter hack" etc.) (verb)- to ride a horse for pleasure, not as training

Hand

A measure equal to a hand's breadth. 1 hand equals four inches. Chiefly used in measuring the height of horses.

Hard keeper

A horse whose weight is hard to maintain.

Headcollar

A British term for halter.

Hock

Hindlimb equivalent to the heel, the main joint on the hind leg.