Non-aligned countries didn't exist? Sorry I need some coffee and I'm feeling a little thick at the moment.
I always thought it was more about Developed/Developing/Undeveloped, mostly in terms of the industrial transition.
But, if we are being honest, it’s used a lot more as “third class”.
I suppose indeed that it is not really a well defined “thing”, like the Silk Road.
Even into the 1960's there were few industrialized nations outside of those two main blocks, so "Third World" quickly lost its explicitly political meaning and became more a description of the level of capital investment and worker productivity.
It was pretty well-defined as political classifications go, and people involved in actual "entities" related to it were aware of and sometimes used the term.
"While engaged in a survey of China, the baron was charged with dreaming up a route for a railway linking Berlin to Beijing. This he named die Seidenstrassen, the Silk Roads. It was not until 1938 that the term Silk Road appeared in English, as the title of a popular book by a Nazi-sympathising Swedish explorer, Sven Hedin."
-- historian William Dalrymple
https://www.theguardian.com/artanddesign/2024/oct/06/the-sil...
But it did exist, and goods were shipped between Europe and China without either side being aware the other existed, which at least I think is pretty darn amazing!