[gone35]

Yes and no[1]:

Due to the complex history of evolving meanings and contexts, there is no clear or agreed-upon definition of the Third World. Some countries in the Communist Bloc, such as Cuba, were often regarded as "Third World". Because many Third World countries were extremely poor, and non-industrialized, it became a stereotype to refer to poor countries as "third world countries", yet the "Third World" term is also often taken to include newly industrialized countries like Brazil, India and China now more commonly referred to as part of BRIC. Historically, some European countries were non-aligned and a few of these were and are very prosperous, including Ireland, Austria, Sweden, Finland, and Switzerland.

The term Third World is still largely used interchangeably with the least developed countries, the Global South and developing countries.

[1] https://en.m.wikipedia.org/wiki/Third_World

[cromulent]

Just yes, I think. If you want to be clear, say "developing nations". If you want to be unclear, say "third world".

there is no clear or agreed-upon definition of the Third World