Aqueduct

Rabbit

Also known as a pacemaker; this is a horse with no expected chance of winning but is used to prompt a quick pace on the front end of the race to the benefit of a stablemate who is a closer.

Exercise Rider

A rider built much like a jockey but is employed for exercising and working out horses in the morning.

Lasix

A medication for the treatment of bleeding in horses that is legal in North America, but not all worldwide jurisdictions.