proprietor vs owner

proprietor and owner both are nouns.

Word	Noun	Adjective	Verb	Adverb
proprietor	Yes	No	No	No
owner	Yes	No	No	No

As nouns, proprietor and owner are synonyms defined as:

proprietor and owner: (law) someone who owns (is legal possessor of) a business

proprietor (noun)	owner (noun)
(law) someone who owns (is legal possessor of) a business	(law) someone who owns (is legal possessor of) a business
	a person who owns something