sommelier vs wine steward

sommelier and wine steward both are nouns.

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

As nouns, sommelier and wine steward are synonyms defined as:

sommelier and wine steward: a waiter who manages wine service in a hotel or restaurant

Other synonyms of sommelier include wine waiter.

sommelier (noun)	wine steward (noun)
a waiter who manages wine service in a hotel or restaurant	a waiter who manages wine service in a hotel or restaurant