Patent Office vs bureau

Patent Office and bureau both are nouns.

Word	Noun	Adjective	Verb	Adverb
Patent Office	Yes	No	No	No
bureau	Yes	No	No	No

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

Patent Office: the government bureau in the Department of Commerce that keeps a record of patents and trademarks and grants new ones
bureau: an administrative unit of government

Other hypernyms of Patent Office include agency, authority, federal agency, government agency, office.

Patent Office (noun)	bureau (noun)
the government bureau in the Department of Commerce that keeps a record of patents and trademarks and grants new ones	furniture with drawers for keeping clothes
	an administrative unit of government