The term "Third World" arose during the Cold War to define countries that remained non-aligned with either NATO or the Warsaw Pact. The United States, Canada, Japan, South Korea, Western European nations and their allies represented the First World, while the Soviet Union, China, Cuba, and their allies represented the Second World. This terminology provided a way of broadly categorizing the nations of the Earth into three groups based on political and economic divisions. Since the fall of the Soviet Union and the end of the Cold War, the term Third World has decreased in use. It is being replaced with terms such as developing countries, least developed countries or the Global South. The concept itself has become outdated as it no longer represents the current political or economic state of the world and historically poor countries have transited different income levels.

The Third World was normally seen to include many countries with colonial pasts in Africa, …Read more on Wikipedia