During the clod war era this term was used to describe the countries that remained nutral politically and economically without aligining with NATO block or the Communist block. But even after end of the cold war this term continues to be used to describe the poorest countries in the world ----now referred to as the developing countris.
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3.
The term Third World arose during the Cold War to define countries that remained non-aligned or neutral with either capitalism and NATO (which along with its allies represented the First World) or communism and the Soviet Union (which along with its allies represented the Second World). This definition provided a way of broadly categorizing the nations of the Earth into three groups based on social, political, and economic divisions. Although the term continues to be used colloquially to describe the poorest countries in the world, this usage is widely disparaged since the term no longer holds any verifiable meaning after the fall of the Soviet Union deprecated the terms First World and Second World. While there is no identical contemporary replacement, common alternatives include developing world and Global South
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6.
During cold war period some countries including India under nehru decided not to join NATO and wanted to remain non aligned to any power block like nato/ceto/ warsaw, even though their goals ware lofty in reality all the poor countries(at that time even Our country was poor thanks to the policy adopted by nehru) started supporting undivided U.S.S.R, these countries were generally referred to as third world countries