So I Googled the origin of the words " Third World" and this is what I found;
A Third World country is a country whose views are not aligned with NATO and capitalism or the Soviet Union and communism. The use of the term "Third World" started during the Cold War and was used to identify which of three categories the countries of the world aligned with.
What is the meaning?
I just googled and got the same result, what this basically means is that these countries don't share the views of the Western Powers with regards to capitalism and more inclined towards the government owning all assets of the country which is basically communism.