The International Court of Justice (ICJ), colloquially the World Court, is the principal judicial organ of the United Nations. It settles legal disputes submitted to it by states and provides advisory opinions on legal questions referred to it by other UN organs and specialized agencies. The ICJ is the only international court that adjudicates general disputes between countries, with its rulings and opinions serving as primary sources of international law. Established in June 1945 by the Charter of the United Nations, the Court began work in April 1946.