EC vs international organisation

EC and international organisation both are nouns.

Word	Noun	Adjective	Verb	Adverb
EC	Yes	No	No	No
international organisation	Yes	No	No	No

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

EC: an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members
international organisation: an international alliance involving many different countries

EC (noun)	international organisation (noun)
an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members	an international alliance involving many different countries