The Union of Soviet Socialist Republics (a very common name, although more formally Russia, the RSFSR, was one of several constituent republics of the USSR).
The Russian Empire; the tsarist empire in Russia lasting from 1721 to 1917.
A country in Eastern Europe and North Asia, bordering on the Pacific and Arctic Oceans and the Baltic, Black, and Caspian Seas; established as an independent country in 1991 upon the dissolution of the Soviet Union, it is the largest country in the world. Co-official name: Russian Federation, formerly the Russian Soviet Federative Socialist Republic (RSFSR) (among other names) from 1917 to 1991. Capital and largest city: Moscow.
RSFSR (the Russian Soviet Federative Socialist Republic) (1917–1991), largest republic of the USSR.
The unofficial term used for the former Russian Republic for a short period after its collapse - from 7 November 1917 (October Revolution) to 19 July 1918 (1st RSFSR Constitution) or to 30 December 1922 (Treaty on the Creation of the USSR). Also used to refer to the Soviet Union as a whole in the early stages.
Soviet Union