NIST vs federal agency

NIST and federal agency both are nouns.

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

As nouns, federal agency is a hypernym of NIST; that is, federal 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
federal agency: an administrative unit of government

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

NIST (noun)	federal 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