National Park Service vs office

National Park Service and office both are nouns.

Word	Noun	Adjective	Verb	Adverb
National Park Service	Yes	No	No	No
office	Yes	No	No	No

As nouns, office is a hypernym of National Park Service; that is, office is a word with a broader meaning than National Park Service:

National Park Service: an agency of the Interior Department responsible for the national parks
office: an administrative unit of government

Other hypernyms of National Park Service include agency, authority, bureau, federal agency, government agency.

National Park Service (noun)	office (noun)
an agency of the Interior Department responsible for the national parks	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