National Park Service vs bureau

National Park Service and bureau both are nouns.

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

As nouns, bureau is a hypernym of National Park Service; that is, bureau 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
bureau: an administrative unit of government

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

National Park Service (noun)	bureau (noun)
an agency of the Interior Department responsible for the national parks	furniture with drawers for keeping clothes
	an administrative unit of government