atomic physics vs barn

atomic physics and barn both are nouns.

Word	Noun	Adjective	Verb	Adverb
atomic physics	Yes	No	No	No
barn	Yes	No	No	No

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