NIST vs government agency

NIST and government agency both are nouns.

Word	Noun	Adjective	Verb	Adverb
NIST	Yes	No	No	No
government agency	Yes	No	No	No

As nouns, government agency is a hypernym of NIST; that is, government agency is a word with a broader meaning than NIST:

NIST: an agency in the Technology Administration that makes measurements and sets standards as needed by industry or government programs
government agency: an administrative unit of government

Other hypernyms of NIST include agency, authority, bureau, federal agency, office.

NIST (noun)	government agency (noun)
an agency in the Technology Administration that makes measurements and sets standards as needed by industry or government programs	an administrative unit of government