Definition of third world
1 : a group of nations especially in Africa and Asia not aligned with either the Communist or the non-Communist blocs
2 : an aggregate of minority groups within a larger predominant culture
3 : the aggregate of the underdeveloped nations of the world
third worlderplay \-ˈwər(-ə)l-dər\ noun, often capitalized T&W
First Known Use of third world
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