service fee vs corkage

service fee and corkage both are nouns.

Word	Noun	Adjective	Verb	Adverb
service fee	Yes	No	No	No
corkage	Yes	No	No	No

As nouns, corkage is a hyponym of service fee; that is, corkage is a word with a more specific, narrower meaning than service fee:

service fee: a percentage of a bill (as at a hotel or restaurant) added in payment for service
corkage: a charge added at a restaurant for every bottle of wine served that was not bought on the premises

service fee (noun)	corkage (noun)
a percentage of a bill (as at a hotel or restaurant) added in payment for service	a charge added at a restaurant for every bottle of wine served that was not bought on the premises