A member state is a state that is a member of an international organization or of a federation or confederation. A member state is a state that is a member of an international organization or of a federation or confederation. The World Trade Organization (WTO) and the International Monetary Fund (IMF) include some members that are not sovereign states; thus, neither organization ever speaks of 'member states'; the WTO has simply 'members' (see WTO members), whereas the IMF calls its members 'member countries'. In history: