coffee shop vs coffee bar

coffee shop and coffee bar both are nouns.

Word	Noun	Adjective	Verb	Adverb
coffee shop	Yes	No	No	No
coffee bar	Yes	No	No	No

As nouns, coffee shop and coffee bar are synonyms defined as:

coffee shop and coffee bar: a small restaurant where drinks and snacks are sold

Other synonyms of coffee shop include cafe, coffeehouse.

coffee shop (noun)	coffee bar (noun)
a small restaurant where drinks and snacks are sold	a small restaurant where drinks and snacks are sold