Soviet Union(redirected from The union of Soviet Socialist Rebublics)
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a former federal republic in E Europe and central and N Asia: the revolution of 1917 achieved the overthrow of the Russian monarchy and the Soviet Union (the USSR) was established in 1922 as a Communist state. It was the largest country in the world, occupying a seventh of the total land surface. The collapse of Communist rule in 1991 was followed by declarations of independence by the constituent republics and the consequent break-up of the Soviet Union.