crude oil vs rock oil

crude oil and rock oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
crude oil	Yes	No	No	No
rock oil	Yes	No	No	No

As nouns, crude oil and rock oil are synonyms defined as:

Other synonyms of crude oil include crude, fossil oil, oil, petroleum.

crude oil (noun)	rock oil (noun)
a dark oil consisting mainly of hydrocarbons	a dark oil consisting mainly of hydrocarbons