Member States - MS
The countries that belong to an international organisation are its 'member states'.
From January 1, 2007, the member states of the European Union are Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the United Kingdom. Several countries which have applied for EU membership (candidate countries and potential candidate countries).
Croatia becomes Member State in 2013.