US Coast Guard vs office

US Coast Guard and office both are nouns.

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

As nouns, office is a hypernym of US Coast Guard; that is, office 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
office: an administrative unit of government

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

US Coast Guard (noun)	office (noun)
an agency of the Department of Transportation responsible for patrolling shores and facilitating nautical commerce	a religious rite or service prescribed by ecclesiastical authorities
	the actions and activities assigned to or required or expected of a person or group
	a job in an organization
	place of business where professional or clerical duties are performed
	professional or clerical workers in an office
	an administrative unit of government
	(of a government or government official) holding an office means being in power