FIRST WORLD: So called developed, capitalist, industrial countries. Usually refers to countries aligned with the United States after World War II, with more or less common political and economic interests: North America, Western Europe, Japan and Australia.
SECOND WORLD: The former communist-socialist, industrial states, includes Eastern Europe (e.g., Poland) and some of the Turk States (e.g., Kazakhstan) as well as China.
THIRD WORLD: all the other countries, primarily refers to the developing countries of Africa, Asia and Latin America.
FOURTH WORLD: Refers to nations of indigenous peoples living within or across state boundaries (nation states).