blue jeans vs Levi's

blue jeans and Levi's both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue jeans	Yes	No	No	No
Levi's	Yes	No	No	No

As nouns, Levi's is a hyponym of blue jeans; that is, Levi's is a word with a more specific, narrower meaning than blue jeans:

blue jeans: (used in the plural) close-fitting trousers of heavy denim for manual work or casual wear
Levi's: a popular brand of jeans

Other hyponyms of blue jeans include levis, distressed jeans.

blue jeans (noun)	Levi's (noun)
(used in the plural) close-fitting trousers of heavy denim for manual work or casual wear	a popular brand of jeans