Many countries include 'Democratic' or 'People's' in their names, even though they are not democratic and do not serve their people. Examples:
Democratic People's Republic of Korea
Lao People's Democratic Republic
People's Democratic Republic of Algeria
Democratic Republic of the Congo
And German Democratic Republic (East Side) in 1949–1990.
None of these states are democratic, power and wealth are concentrated in the hands of a small ruling elite. Who are they fooling with these names?
if you stick strictly to the name "united states" then yes, it's the first entity to name themselves this. later entities include the united states of belgium but they appear later (1790).
however, the netherlands used the name "united provinces" and "(republic of the seven) united netherlands" from 1588, sooooo I guess it can count if you make your question broad?
