barrel vs keg

barrel and keg both are nouns.

Word	Noun	Adjective	Verb	Adverb
barrel	Yes	No	Yes	No
keg	Yes	No	No	No

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

Other hyponyms of barrel include beer barrel, beer keg, butt, hogshead, pickle barrel, shook, tun, wine barrel, wine cask.

barrel (noun)	keg (noun)
a cylindrical container that holds liquids	small cask or barrel
a tube through which a bullet travels when a gun is fired	the quantity contained in a keg
any of various units of capacity
the quantity that a barrel (of any size) will hold
a bulging cylindrical shape; hollow with flat ends

barrel (verb)	keg (verb)
put in barrels