executive agency vs bureau

executive agency and bureau both are nouns.

Word	Noun	Adjective	Verb	Adverb
executive agency	Yes	No	No	No
bureau	Yes	No	No	No

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

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

executive agency (noun)	bureau (noun)
an agency of the executive branch of government	furniture with drawers for keeping clothes
	an administrative unit of government