Official entrants that will not run unless other horses are scratched and vacancies occur in the field.
An entered horse that will race only if a scratch occurs (at or prior to scratch time) in the body of the field.
Horse officially entered in a race, but not permitted to start unless the field is reduced by scratch(es).
When more horses are entered in a race than can be accommodated by the size of the track (i.e., 8, 10, or 12 horse starting gate) normally four also eligible horses are drawn and may move into the starting field in the event of a scratch or withdrawal. The other horses are excluded and are placed on a preferred list for future races.
Horses officially entered in a race, but not permitted to start due to a full field of runners. The horse may “scratch” into the race if an eligible horse is withdrawn.
A horse entered in the race but who cannot start unless another horse is scratched.