Census Bureau vs bureau

Census Bureau and bureau both are nouns.

Word	Noun	Adjective	Verb	Adverb
Census Bureau	Yes	No	No	No
bureau	Yes	No	No	No

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

Census Bureau: the bureau of the Commerce Department responsible for taking the census; provides demographic information and analyses about the population of the United States
bureau: an administrative unit of government

Other hypernyms of Census Bureau include agency, authority, federal agency, government agency, office.

Census Bureau (noun)	bureau (noun)
the bureau of the Commerce Department responsible for taking the census; provides demographic information and analyses about the population of the United States	furniture with drawers for keeping clothes
	an administrative unit of government