footrace vs marathon

footrace and marathon both are nouns.

Word	Noun	Adjective	Verb	Adverb
footrace	Yes	No	No	No
marathon	Yes	No	No	No

As nouns, marathon is a hyponym of footrace; that is, marathon is a word with a more specific, narrower meaning than footrace:

Other hyponyms of footrace include fun run, funrun, obstacle race, steeplechase, track event.

footrace (noun)	marathon (noun)
a race run on foot	any long and arduous undertaking
	a footrace of 26 miles 385 yards