DARPA vs bureau

DARPA and bureau both are nouns.

Word	Noun	Adjective	Verb	Adverb
DARPA	Yes	No	No	No
bureau	Yes	No	No	No

As nouns, bureau is a hypernym of DARPA; that is, bureau is a word with a broader meaning than DARPA:

DARPA: the central research and development organization for the United States Department of Defense; responsible for developing new surveillance technologies since 9/11
bureau: an administrative unit of government

Other hypernyms of DARPA include agency, authority, federal agency, government agency, office.

DARPA (noun)	bureau (noun)
the central research and development organization for the United States Department of Defense; responsible for developing new surveillance technologies since 9/11	furniture with drawers for keeping clothes
	an administrative unit of government