USA vs federal office

USA and federal office both are nouns.

Word	Noun	Adjective	Verb	Adverb
USA	Yes	No	No	No
federal office	Yes	No	No	No

USA (noun)	federal office (noun)
the army of the United States of America; the agency that organizes and trains soldiers for land warfare	a department of the federal government of the United States
North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776