Census Bureau vs federal agency

Census Bureau and federal agency both are nouns.

Word	Noun	Adjective	Verb	Adverb
Census Bureau	Yes	No	No	No
federal agency	Yes	No	No	No

As nouns, federal agency is a hypernym of Census Bureau; that is, federal agency 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
federal agency: an administrative unit of government

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

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