First World

The concept of First World originated during the Cold War and comprised countries that were aligned with United States and the rest of NATO and opposed the Soviet Union and/or communism during the Cold War. Since the collapse of the Soviet Union in 1991, the definition has instead largely shifted to any country with little political risk and a well-functioning democracy, rule of law, capitalist economy, economic stability, and high standard of living. Various ways in which modern First World countries are usually determined include GDP, GNP, literacy rates, life expectancy, and the Human Development Index.[1] In common usage, "first world" typically refers to "the highly developed industrialized nations often considered the westernized countries of the world".[2]

The "Three Worlds" of the Cold War era, April  August 1975
  First World: Western Bloc led by the USA, Japan, United Kingdom and their allies
  Second World: Eastern Bloc led by the USSR, China, and their allies
  Third World: Non-Aligned and neutral countries