federal agency vs office

federal agency and office both are nouns.

Word	Noun	Adjective	Verb	Adverb
federal agency	Yes	No	No	No
office	Yes	No	No	No

As nouns, federal agency and office are synonyms defined as:

Other synonyms of federal agency include agency, authority, bureau, government agency.

federal agency (noun)	office (noun)
an administrative unit of government	a religious rite or service prescribed by ecclesiastical authorities
	the actions and activities assigned to or required or expected of a person or group
	a job in an organization
	place of business where professional or clerical duties are performed
	professional or clerical workers in an office
	an administrative unit of government
	(of a government or government official) holding an office means being in power