Bureau of Customs vs office

Bureau of Customs and office both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bureau of Customs	Yes	No	No	No
office	Yes	No	No	No

As nouns, office is a hypernym of Bureau of Customs; that is, office is a word with a broader meaning than Bureau of Customs:

Bureau of Customs: the agency of the Treasury Department that enforces import tariffs
office: an administrative unit of government

Other hypernyms of Bureau of Customs include agency, authority, bureau, federal agency, government agency.

Bureau of Customs (noun)	office (noun)
the agency of the Treasury Department that enforces import tariffs	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