What does racing form mean with regard to horses?

Racing form is the set of details about each horse in a race that bookmakers use to set odds for betting. At a minimum, the information contains the horse's placing in its last few races, its name, its trainer, its jockey and the weight it carries in a given race.

The form is usually given in a the form of a single line per horse, but where additional details such as the horse's parentage and its performance on a particular track are added, the listing can stretch over several lines. Some racing form charts also include information about horses' running styles and preferred types of course.