server vs sommelier

server and sommelier both are nouns.

Word	Noun	Adjective	Verb	Adverb
server	Yes	No	No	No
sommelier	Yes	No	No	No

As nouns, sommelier is a hyponym of server; that is, sommelier is a word with a more specific, narrower meaning than server:

Other hyponyms of server include carhop, counterperson, wine steward, wine waiter, waitress.

server (noun)	sommelier (noun)
utensil used in serving food or drink	a waiter who manages wine service in a hotel or restaurant
(computer science) a computer that provides client stations with access to files and printers as shared resources to a computer network
a person whose occupation is to serve at table (as in a restaurant)
(court games) the player who serves to start a point