You are right, just like developed country. Your comment reminded me of this very interesting video that compares the US, Cuba and Chile: http://www.gapminder.org/videos/gapmindervideos/gapcast-6-ch...

not exactly.. there was a proper term.. fourth world as well.

for 15-20 years, third world in military terms at least, meant the signatory of NAM movement. fourth world was anyone left after that.