Superfecta

A wager involving choosing the first, second, third, and fourth horses in one race in the exact order. A superfecta box involves paying more to ensure they can finish in any order in the top four spots.

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.

Scratch

A horse is a scratch when injury or other necessity causes it to be withdrawn from the race.