waiter vs wine steward

waiter and wine steward both are nouns.

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

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

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

waiter (noun)	wine steward (noun)
a person whose occupation is to serve at table (as in a restaurant)	a waiter who manages wine service in a hotel or restaurant
a person who waits or awaits