Scratch

A horse is a scratch when injury or other necessity causes it to be withdrawn from the race.

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.

Condition Book

A list of upcoming races issued by the racing secretary, where the conditions of races to be run over the next few weeks are written.