the political, military, and ideological barrier erected by the Soviet Union (Union of Soviet Socialist Republics) after World War II to seal off itself and its dependent eastern European allies from open contact with the West and other noncommunist areas. The term Iron Curtain had been in occasional and varied use as a metaphor since the 19th century, but it came to prominence only after it was used by the former British prime minister Winston Churchill (Churchill, Sir Winston) in a speech at Fulton, Missouri, U.S., on March 5, 1946, when he said of the communist (communism) states, “From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the Continent.”

The restrictions and the rigidity of the Iron Curtain were somewhat reduced in the years following Joseph Stalin (Stalin, Joseph)'s death in 1953, although the construction of the Berlin Wall in 1961 restored them. The Iron Curtain largely ceased to exist in 1989–90 with the communists' abandonment of one-party rule in eastern Europe.