The Eurozone (also called Euro area or Euroland) is the set of countries in the European Union which have adopted the Euro (€) currency. The European Central Bank is responsible for managing the supply of money within the eurozone and political decisions are taken by the "euro group", which is a meeting of the politicians from each euro country in charge of that country's economy.
EU members that are not part of the Eurozone are Denmark, Sweden, Poland, Czech Republic, Hungary, Bulgaria, and Romania.