Show Wager

Betting on a horse to finish in the first three spots, which pays out the same whether they win or run second or third.

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A horse is a scratch when injury or other necessity causes it to be withdrawn from the race.