crude oil vs oil

crude oil and oil both are nouns.

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

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

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

As nouns, oil is a hypernym of crude oil; that is, oil is a word with a broader meaning than crude oil:

crude oil: a dark oil consisting mainly of hydrocarbons
oil: a slippery or viscous liquid or liquefiable substance not miscible with water

Other hypernyms of crude oil include fossil fuel.

crude oil (noun)	oil (noun)
a dark oil consisting mainly of hydrocarbons	oil paint containing pigment that is used by an artist
	any of a group of liquid edible fats that are obtained from plants
	a slippery or viscous liquid or liquefiable substance not miscible with water
	a dark oil consisting mainly of hydrocarbons

crude oil (verb)	oil (verb)
	administer an oil or ointment to; often in a religious ceremony of blessing
	cover with oil, as if by rubbing