pinto horse, American light horse, characterized by large, irregular color markings-most commonly black (or dark) and white. Horses of this pattern, known regionally as "paints" [Span. pinto=painted] were favored by the buffalo hunters of the American Great Plains. Although the pinto coloring may occur in various horses, a pinto breed has been developed and was recognized in the United States in 1963. It is a popular general-purpose riding horse.