Common Market vs EEC

Common Market and EEC both are nouns.

Word	Noun	Adjective	Verb	Adverb
Common Market	Yes	No	No	No
EEC	Yes	No	No	No

As nouns, Common Market and EEC are synonyms defined as:

Common Market and EEC: an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members

Other synonyms of Common Market include EC, EU, Europe, European Community, European Economic Community, European Union.

Common Market (noun)	EEC (noun)
an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members	an international organization of European countries formed after World War II to reduce trade barriers and increase cooperation among its members