barn vs cowshed

barn and cowshed both are nouns.

Word	Noun	Adjective	Verb	Adverb
barn	Yes	No	No	No
cowshed	Yes	No	No	No

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

barn: an outlying farm building for storing grain or animal feed and housing farm animals
cowshed: a barn for cows

Other hyponyms of barn include byre, cow barn, cowbarn, cowhouse, tithe barn.

barn (noun)	cowshed (noun)
an outlying farm building for storing grain or animal feed and housing farm animals	a barn for cows
(physics) a unit of nuclear cross section; the effective circular area that one particle presents to another as a target for an encounter