system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: We often hear about first world and third world countries/problems ect. But why do we never hear about second world?
gpt
Because the "Second" world doesn't really exist anymore.

Some definitions:

The "First" World - The United States and its Allies, Capitalists countries

The "Second" World - The USSR and its Allies, Communist countries

The "Third" World - Developing countries that the 1st and 2nd world fight over.

So the end of the Cold War essentially ended the "Second" world.  The original definitions have nothing to do with economics (like they do today) but with where you were positioned in the Cold War.