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 , tr. Soyuz Sovetskikh Sotsialisticheskikh Respublik, abbreviated СССР, SSSR. The common short name is Soviet Union, from lang: 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 its largest and dominant constituent state—continued to be commonly used throughout the state'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, most of Finland, and Alaska. The Soviet Union became the primary model for future Communist states 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.

From 1945 until dissolution in 1991—a period known as the Cold War—the Soviet Union and the United States of America were the two world superpowers that dominated the global agenda of economic policy, foreign affairs, military operations, cultural exchange, scientific advancements including the pioneering of space exploration, and sports (including the Olympic Games and various world championships).

Initially established as a union of four Soviet Socialist Republics, the USSR grew to contain 15 constituent or "union republics" by 1956: Armenian SSR, Azerbaijan SSR, Byelorussian SSR, Estonian SSR, Georgian SSR, Kazakh SSR, Kirghiz SSR, Latvian SSR, Lithuanian SSR, Moldavian SSR, Russian SFSR, Tajik SSR, Turkmen SSR, Ukrainian SSR and Uzbek SSR. (From annexation of the Estonian SSR on August 6, 1940 up to the reorganization of the Karelo-Finnish SSR into the Karelian ASSR on July 16, 1956, the count of "union republics" was 16.)

History

main: History of the Soviet Union

The Soviet Union is traditionally considered to be the successor of the Russian Empire and of its short-lived successor, The Provisional Government under Georgy Yevgenyevich Lvov and then Alexander Kerensky. The last Russian Tsar, Nicholas II, ruled until March, 1917 when the Empire was overthrown and a short-lived Russian provisional government took power, the latter to be overthrown in November 1917 by Vladimir Lenin. From 1917 to 1922, the predecessor to the Soviet Union was the Russian Soviet Federative Socialist Republic (RSFSR), which was an independent country as well as other Soviet republics at the time. The Soviet Union was officially established in December 1922 as the union of the Russian (colloquially known as Bolshevist Russia), Ukrainian, Belarusian, and Transcaucasian Soviet republics ruled by Bolshevik parties.