US Coast Guard vs authority

US Coast Guard and authority both are nouns.

Word	Noun	Adjective	Verb	Adverb
US Coast Guard	Yes	No	No	No
authority	Yes	No	No	No

As nouns, authority is a hypernym of US Coast Guard; that is, authority is a word with a broader meaning than US Coast Guard:

US Coast Guard: an agency of the Department of Transportation responsible for patrolling shores and facilitating nautical commerce
authority: an administrative unit of government

Other hypernyms of US Coast Guard include coastguard, agency, bureau, federal agency, government agency, office.

US Coast Guard (noun)	authority (noun)
an agency of the Department of Transportation responsible for patrolling shores and facilitating nautical commerce	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