First world countries, were those allied with the United States. Second world countries were those allied with the Soviet Union. Third world countries were those who allied with neither East or West as members of the 'Non-Allied Movement'. Nigeria was a member of this body. However, fast forward to the end of the cold war. read more
3rd world countries were the non-aligned countries during the cold world era but it had come to mean the non-functioning countries characterised by dictatorship and poor economy so yes Nigeria is a developing third world country. read more