Dead Heat

Two or more horses finishing so close at the wire, that they were unable to be separated on a photo finish and deemed to have tied.

Scratch

A horse is a scratch when injury or other necessity causes it to be withdrawn from the race.

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.