Define Union Of Soviet Socialist Republics Meaning

you would call this "Soviet Union" in the modern times

The Soviet Union, officially the Union of Soviet Socialist Republics (USSR), was a federal socialist state in Northern Eurasia that existed from 1922 to 1991 and was the largest country in the world. Nominally a union of multiple national Soviet republics, in practice its government and economy were highly centralized,and it was communist.