Lasix

A medication for the treatment of bleeding in horses that is legal in North America, but not all worldwide jurisdictions.

Apprentice

A new jockey who has not ridden a certain number of winners in a specified time period.

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.