Толковый словарь английского языка Oxford English Reference - marathon

n. 1 a long-distance running race, usu. of 26 miles 385 yards (42.195 km). 2 a long-lasting or difficult task, operation, etc. (often attrib.: a marathon shopping expedition). Derivatives marathoner n. Etymology: Marathon in Greece, scene of a victory over the Persians in 490 BC: a messenger was said to have run to Athens with the news, but the account has no authority