Racecard is a printed card used in horse racing giving information about races, principally the horses running in each particular race. Racecards are often given in newspapers. Also known as a race book, which in this case is a small booklet issued for use at a race meeting.
A typical racecard lists information not only about the horse's name, but also its age and the weight it has to carry in the race. The rider and trainer are listed, plus figures indicating the horse's recent form.