Tack:  The name given to the collection of stuff that goes on a horse.  Saddle, bridle, girth, etc.  May also be used as a verb, to mean putting all the stuff on to the horse.

Tail male:  The sire line, or top line in a pedigree, back to the original sire.

Texture:  Condition of the muscle structure (whether firm or spongy).

Thoroughbred:  A breed of horse known for its long, graceful limbs and athletic ability.  Thoroughbreds are used in horse racing.  A pure-bred blood horse which traces its ancestry back to horses entered in Weatherby's Stud Book Nos. 1-5, first published in 1808.  All Thoroughbred horses include the Darley Arabian, the Byerley Turk or the Godolphin Arabian in their pedigrees.  (It is important to distinguish the breed from any purebred, since the term has been used to designate the latter.)

Trot:  A two-beat gait in which diagonal front and rear feet strike the ground at the same time.  It can be performed at varying speeds:  as a slow and easy gait, as the snappy, quick trot used in showing, and as the reaching, flat-out stride of the racing trotter.

Trotter:  Horse or pony that races in harness; it may either trot or pace.

Trotting pitch:  Raised croup of the Trotter.