From Citizendium, the Citizens' Compendium
Yugoslavia (Slovenian and Croatian: Jugoslavia; Serbian and Macedonian: Југославија) is the name for different political entities that existed on the Balkan Peninsula in Europe during the 20th century. Six currently existent countries were at some time included in Yugoslavia: Slovenia, Croatia, Bosnia and Herzegovina, Serbia, Montenegro and Macedonia.
The Kingdom of Yugoslavia (December 1, 1918 – April 17, 1941), also known as the First Yugoslavia, was a monarchy formed as the "Kingdom of Serbs, Croats and Slovenes" after the World War I and re-named on 6 January 1929 by Alexander I of Yugoslavia. It was invaded on 6 April 1941 by the Axis powers and capitulated eleven days later.
The Socialist Federal Republic of Yugoslavia (November 29, 1943 – June 25, 1991), a socialist successor state to the Kingdom of Yugoslavia, existed under various names, including the "Democratic Federation of Yugoslavia (DFY)" (1943), the "Federal People's Republic of Yugoslavia (FPRY)" (1946), and the "Socialist Federal Republic of Yugoslavia (SFRY)" (1963). Starting in 1991, the SFRY dissolved in the Yugoslav Wars which followed the secession of most of the constituent republics.
The Federal Republic of Yugoslavia (FRY) (April 27, 1992 – February 4, 2003), was a federation on the territory of the two remaining republics of Serbia and Montenegro. The Union of Serbia and Montenegro was formed on February 4, 2003, and officially abolished the name "Yugoslavia." On June 3 and June 5, 2006, Montenegro and Serbia respectively declared their independence, ending the last remnant of the former Yugoslav federation.