From Longman Dictionary of Contemporary EnglishThird WorldˌThird ˈWorld noun → the Third World —Third World adjective Third World debtThird World, thethe Third WorldˌThird ˈWorld, the the poorer countries of the world that are not industrially developed, including most of Africa and parts of Asia and of Central and South America. Some people think this expression is offensive, and the Third World can also be called the South. → compare First World —Third-World adjective Third-World economiesFrom Longman Business DictionaryThird WorldˌThird ˈWorld noun the Third WorldECONOMICS the poorer countries of the world, that are not industrially developedThe bank had stakes in several operations in the Third World. —Third World adjectiveThird World countries