one of a hardy breed of riding horses, developed in the North American West, having a mottled hide, vertically striped hoofs, and eyes that show a relatively large proportion of white.
Origin of Appaloosa
1920–25,Americanism; origin uncertain; perhaps to be identified with Opelousa a Louisiana Indian tribal name (Compare Opelousas poney, recorded in a German text of 1849), though the breed is traditionally associated with the Nez Percé Indians and the Palouse River (W Idaho)
breed of horses favored by Indian tribes in U.S. West, 1849, either from Opelousa in Louisiana or from Palouse Indians, who lived near the river of that name in Idaho, in which case it probably is a Nez Percé word. Opelousa is perhaps from Choctaw api losa "black body;" while Palouse is from Sahaptin palou:s "what is standing up in the water."