corn oil vs vegetable oil

corn oil and vegetable oil both are nouns.

Word	Noun	Adjective	Verb	Adverb
corn oil	Yes	No	No	No
vegetable oil	Yes	No	No	No

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

corn oil: oil from the germs of corn grains
vegetable oil: any of a group of liquid edible fats that are obtained from plants

Other hypernyms of corn oil include oil.

corn oil (noun)	vegetable oil (noun)
oil from the germs of corn grains	any of a group of liquid edible fats that are obtained from plants