benzene vs benzene ring

benzene and benzene ring both are nouns.

Word	Noun	Adjective	Verb	Adverb
benzene	Yes	No	No	No
benzene ring	Yes	No	No	No

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

benzene: a colorless liquid hydrocarbon; highly flammable; carcinogenic; the simplest of the aromatic compounds
benzene ring: a closed chain of 6 carbon atoms with hydrogen atoms attached

Other hyponyms of benzene include benzene formula, benzene nucleus, Kekule formula.

benzene (noun)	benzene ring (noun)
a colorless liquid hydrocarbon; highly flammable; carcinogenic; the simplest of the aromatic compounds	a closed chain of 6 carbon atoms with hydrogen atoms attached