A former country of eastern Europe and northern Asia with coastlines on the Baltic and Black seas and the Arctic and Pacific oceans. It was established in December 1922 with the union of the Russian SFSR (proclaimed after the Russian Revolution of 1917) and various other soviet republics, including Belorussia and the Ukraine. In 1991 a number of consituent republics declared their independence, and the USSR was officially dissolved on December 31, 1991. Moscow was the capital.
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved.