The countries of Africa, Asia, and South America are sometimes referred to all together as the Third World, especially those parts that are poor, do not have much power, and are not considered to be highly developed. Compare First World. development in the Third World. Third World debt. the poorer countries of the world that are not industrially developed. Some people now consider this expression offensive. World. Political designation originally used (1963) to describe those states not part of the first world the capitalist, economically developed states led by the U.S. or the second world the communist states led by the Soviet Union. The third world principally consists of the developing world, former colonies of Africa, Asia, and Latin America. With the end of the Cold War and the increased economic competitiveness of some developing countries, the term has lost its analytic clarity