It simply means that the horse is eligible to race, but they will need a horse already involved to be scratched in order to line up. This could be a key term seen in big graded races. This is determined from previous performances. Horses involved in these races will carry different weights to ensure that it is a level playing field. These races are restricted to certain horses mainly revolving around prize money won or age. While many will be most interested in betting on the big graded races, such as the Kentucky Derby, horses will first have to run in allowance races. We will go through some of the most important terms, and give detailed explanations to help broaden your knowledge of racing. However, understanding horse racing terms for dummies is easier than many believe, and this page will be helpful to those looking to get a deeper understanding revolving around everything to do with the sport. There are few sports like horse racing, which means that it can often be daunting to newcomers to the sport when it comes to understanding the terminology used. Horse Racing Terms for Dummies: Glossary to Know