NATO vs world organisation

NATO and world organisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
NATO	Yes	No	No	No
world organisation	Yes	No	No	No

As nouns, world organisation is a hypernym of NATO; that is, world organisation is a word with a broader meaning than NATO:

NATO: an international organization created in 1949 by the North Atlantic Treaty for purposes of collective security
world organisation: an international alliance involving many different countries

NATO (noun)	world organisation (noun)
an international organization created in 1949 by the North Atlantic Treaty for purposes of collective security	an international alliance involving many different countries