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.

Bolt

A sudden veering to the inside or outside rail, often caused by the horse spooking or shying from something.

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.