United States Navy vs authority

United States Navy and authority both are nouns.

Word	Noun	Adjective	Verb	Adverb
United States Navy	Yes	No	No	No
authority	Yes	No	No	No

As nouns, authority is a hypernym of United States Navy; that is, authority is a word with a broader meaning than United States Navy:

United States Navy: the navy of the United States of America; the agency that maintains and trains and equips combat-ready naval forces
authority: an administrative unit of government

Other hypernyms of United States Navy include agency, bureau, federal agency, government agency, office.

United States Navy (noun)	authority (noun)
the navy of the United States of America; the agency that maintains and trains and equips combat-ready naval forces	the power or right to give orders or make decisions
	official permission or approval
	freedom from doubt; belief in yourself and your abilities
	an authoritative written work
	an administrative unit of government
	an expert whose views are taken as definitive
	(usually plural) persons who exercise (administrative) control over others