Source: Dictionary.com
Quote:
mar·a·thon
–noun
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.
|
So depending on which definition you wish to take a 5k run can be a marathon.
Good for you for running more than 5k, but don't hype your accomplishments by downgrading others.