/mar"euh thon', -theuhn/ , n.
1. a foot race over a course measuring 26 mi. 385 yd. (42 km 195 m).
2. any long-distance race.
3. any contest, event, or the like, of great, or greater than normal, length or duration or requiring exceptional endurance: a dance marathon; a sales marathon.
[ 1895-1900; allusion to Pheidippides' 26-mi. (42-km) run from MARATHON to Athens to carry news of the Greek victory over the Persians in 490 B.C. ]