USSR is an abbreviation for Union of Soviet Socialist Republics.   This title is also sometimes shortened to the Soviet Union.

Because Russia has a different alphabet (called the Cyrillic alphabet) USSR is spelled CCCP in Cyrillc.  CCCP stands for Союз Советских Социалистических Республик. Transliterated, this reads as Soyuz Sovetskikh Sotsialisticheskikh Respublik, which gives rise to yet another abbreviation, SSSR, although this is less commonly used in English.

The word Soyuz means union, and the word Soviet means council.

meaning-of-ussr-flag

May people also ask ‘What does the Soviet flag mean?‘ The Soviet flag is a hammer and sickle design on a red background, with a star just above. The hammer and sickle represent the union of workers and peasants, while the star represents the Communist Party.