server vs wine steward

server and wine steward both are nouns.

Word	Noun	Adjective	Verb	Adverb
server	Yes	No	No	No
wine steward	Yes	No	No	No

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

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

server (noun)	wine steward (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