This is an out-dated terminology: inappropriate, impertinent, and irrelevant in today’s world where meaningful classifications could be:
(a) Countries which are industrially and economically developing.
(b) Countries which are free from religious laws/authorities telling people what to do and what not to do.
(c) Countries whose citizens enjoy full freedom to hold and express their opinions, and periodically choose their political leaders.
(d) Countries which are militarily strong enough to defend their borders.
(e) Countries which don’t depend on foreign economic assistance for their survival and development.
(f) Countries which manage their own affair, those that meddle in the affairs of other countries.