A Maiden race horse is the term that refers to a race horse that has yet to win a single race. The races are generally run for younger more inexperienced horses at two and three. However, many maidens never "break their maiden", and will continue to race at later ages, often retiring winless.
Zippy Chippy is among the most famous maidens of all time, going 0 for 100 in his career. Maiden races are not necessarily for less talented horses, just less proven ones. For instance, maiden races at prestigious tracks like Saratoga, Keeneland Race Course, and Santa Anita often contain future stars of the game, as trainers unveil some of their most talented precocious horses. Furthermore, many horse players enjoy maiden races as they allegedly allow for more speculation and esoteric knowledge of racing, since maiden horses often show with few or no previous races to gauge performance.