What is the definition of a third world country and where did it come from? Are there first, second, and fourth world countries?
Coined by French demographer Alfred Sauvy in the 1950s, "third world" refers to economically underdeveloped countries. Sauvy was making an analogy between pre-industrial nations with the poor of pre-Revolutionary France, who were considered part of the "third estate."
When the concept became popularized, it was extended to include "first" (industrialized or westernized) and "second" (communist) worlds. These distinctions have become less useful with the end of the Cold War.
The concept of the "third world" still rings true as there are many nations with high infant mortality, high rates of poverty, and dependence on industrialized nations.
—The Fact Monster