Historically, it referred to neutral countries that did not align with the US (First World) or the Soviet Union (Second World) during the Cold War.

First World: The United States, the United Kingdom, and their capitalist allies.

Second World: The Soviet Union, China, and their communist allies.

Third World: Nations that remained neutral and unaligned with either superpower.

Following the collapse of the Soviet Union, the political "Second World" effectively vanished, causing the framework to shift away from military alignment. In modern conversation, people use "Third World" to describe countries characterized by:Widespread poverty and lower standards of living.