The Cold War was a period of tension between the United States and the Soviet Union that lasted from 1945 to 1991. During this time, the two countries were considered to be the main Cold War foes. The term 'REDS' is an acronym for the Union of Soviet Socialist Republics (USSR), which was the official name of the Soviet Union during the Cold War. The term 'SOVIETS' refers to the citizens of the Soviet Union.