Minus Pool

A pari-mutuel pool – typically a show pool - where one horse is so heavily bet that after deductions there is not enough money left to cover the prescribed minimum on each bet.

Trifecta

A wager picking the first, second and third horses in the exact order. A trifecta box means paying more to ensure the horses can finish in any order in the top three spots.

Scratch

A horse is a scratch when injury or other necessity causes it to be withdrawn from the race.