European Union (EU)
a supranational organization composed of twenty-eight European countries, formally established by the 1992 Maastricht Treaty. The EU’s objectives include the economic, political, and security integration of its members, accomplished through such methods as removal of trade barriers, free circulation of EU citizens among certain member countries, and use of a common currency, the euro, by nineteen members. The EU is the largest U.S. trading partner, and many of its members are among the most important U.S. allies.