(foaled 1917) U.S. Thoroughbred racehorse. In two seasons (1919-20), he won 20 of 21 races, including the Preakness and Belmont stakes. (He did not run in the Kentucky Derby.) He sired 64 stakes horses, including War Admiral, a Triple Crown winner (1937). In a 1950 Associated Press poll, Man o' War was voted the greatest horse of the first half of the 20th century