The concept of the First World was originally one of the "Three Worlds" formed by the global political landscape of the Cold War, as it grouped together those countries that were aligned with the Western Bloc of the United States. This grouping was directly opposed to the Second World, which similarly grouped together those countries that were aligned with the Eastern Bloc of the Soviet Union. However, as the Cold War ended with the dissolution of the Soviet Union in 1991, the definition largely shifted to instead refer to any country that boasts a well-functioning democratic system with little prospects of political risk, in addition to a strong rule of law, a capitalist economy with economic stability, and a high standard of living. Various ways in which these metrics are assessed are through the examination of a country's GDP, GNP, literacy rate, life expectancy, and Human Development Index. In colloquial usage, "First World" typically refers to "the highly developed industrialized nations often considered the Westernized countries of the world".
After World War II, the world split into two large geopolitical blocs, separating into spheres of communism and capitalism. This led to the Cold War, during which the term First World was often used because of its political, social, and economic relevance. The term itself was first introduced in the late 1940s by the United Nations. Today, the terms are slightly outdated and have no official definition. However, the "First World" is generally thought of as the capitalist, industrial, wealthy, and developed countries. This definition includes the countries of North America and Western Europe, Japan, South Korea, and Australia. In contemporary society, the First World is viewed as countries that have the most advanced economies, the greatest influence, the highest standards of living, and the greatest technology. After the Cold War, these countries of the First World included member states of NATO, U.S.