Bolt

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

Colt

A male horse that is four years of age or under.

Bobble/Stumble

A slip or a duck from a horse trying to leave the starting gates, often caused by the surface giving way under the feet. This can range from a mild misstep to a stumble down to their knees.