The Union of Soviet Socialist Republics (USSR) was a constitutionally socialist state that existed in Eurasia from 1922 to 1991. The name is a translation of the Russian: Ru-CCCP.ogg, tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik, abbreviated СССР, SSSR. The common short name is Soviet Union, from Советский Союз, Sovetskiy Soyuz. A soviet is a council, the theoretical basis for the socialist society of the USSR. Emerging from the Russian Empire following the Russian Revolution of 1917 and the Russian Civil War of 1918–1921, the USSR was a union of several Soviet republics, but the synecdoche Russia — after the Russian SFSR, its largest and most populous constituent state — continued to be commonly used throughout the country's existence. The geographic boundaries of the USSR varied with time, but after the last major territorial annexations of the Baltic states, eastern Poland, Bessarabia, and certain other territories during World War II, from 1945 until dissolution, the boundaries approximately corresponded to those of late Imperial Russia, with the notable exclusions of Poland and most of Finland. As the largest and oldest constitutionally communist state in existence, the Soviet Union became the primary model for future communist nations during the Cold War; the government and the political organization of the country were defined by the only political party, the Communist Party of the Soviet Union. (via Wikipedia)