main office vs home office

main office and home office both are nouns.

Word	Noun	Adjective	Verb	Adverb
main office	Yes	No	No	No
home office	Yes	No	No	No

As nouns, main office and home office are synonyms defined as:

main office and home office: (usually plural) the office that serves as the administrative center of an enterprise

Other synonyms of main office include central office, headquarters, home base.

main office (noun)	home office (noun)
(usually plural) the office that serves as the administrative center of an enterprise	(usually plural) the office that serves as the administrative center of an enterprise