service door vs service entrance

service door and service entrance both are nouns.

Word	Noun	Adjective	Verb	Adverb
service door	Yes	No	No	No
service entrance	Yes	No	No	No

As nouns, service door and service entrance are synonyms defined as:

service door and service entrance: an entrance intended for the use of servants or for delivery of goods and removal of refuse

Other synonyms of service door include servant's entrance.

service door (noun)	service entrance (noun)
an entrance intended for the use of servants or for delivery of goods and removal of refuse	an entrance intended for the use of servants or for delivery of goods and removal of refuse