Russian Empire
The Russian Empire, also known as Imperial Russia or simply Russia, was an empire that existed across Eurasia and North America from 1721, following the end of the Great Northern War, until the Republic was proclaimed by the Provisional Government that took power after the February Revolution of 1917.
Russia
The Russian Soviet Federative Socialist Republic (called "Russian Socialist Federative Soviet Republic" at the time), together with the Ukrainian, Byelorussian, and Transcaucasian Soviet Socialist Republics, formed the Union of Soviet Socialist Republics (USSR), or Soviet Union, on December 30, 1922. Out of the 15 republics that would make up the USSR, the largest in size and over half of the total USSR population was the Russian SFSR, which came to dominate the union for its entire 69-year history.