coffee bar vs estaminet

coffee bar and estaminet both are nouns.

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

As nouns, estaminet is a hyponym of coffee bar; that is, estaminet is a word with a more specific, narrower meaning than coffee bar:

coffee bar: a small restaurant where drinks and snacks are sold
estaminet: a small (and usually shabby) cafe selling wine and beer and coffee

Other hyponyms of coffee bar include caff, cybercafe, espresso shop, pull-in, pull-up.

coffee bar (noun)	estaminet (noun)
a small restaurant where drinks and snacks are sold	a small (and usually shabby) cafe selling wine and beer and coffee