Tack
The equipment the horse wears, including saddle and bridle. A jockey typically has their own racing saddle, placed on each horse they ride just before the race.
Exercise Rider
A rider built much like a jockey but is employed for exercising and working out horses in the morning.
Bullet
A bullet, or bullet workout, is a workout that was clocked as the best time for a certain distance on a given day.

