A lot vs. Alot: 9 Grammatical Pitfalls
in reference to the Soviet occupation of Eastern Europe, famously coined by Winston Churchill March 5, 1946, in speech at Westminster College, Fulton, Missouri, but it had been used earlier in this context (e.g. by U.S. bureaucrat Allen W. Dulles at a meeting of the Council on Foreign Relations, Dec. 3, 1945). The figurative sense of "impenetrable barrier" is attested from 1819, and the specific sense of "barrier at the edge of the sphere of influence of the Soviet Union" is recorded from 1920. During World War II, Goebbels used it in German (ein eiserner Vorhang) in the same sense. Its popular use in the U.S. dates from Churchill's speech.
The former division between the communist nations of eastern Europe — the Eastern Bloc — and the noncommunist nations of western Europe. The term refers to the isolation that the Soviet Union imposed on its satellites in the Eastern Bloc and to the repressive measures of many Eastern Bloc governments. (See Berlin Wall and cold war.)
Note: The expression Iron Curtain was coined by Winston Churchill, who was prime minister of Britain in World War II. Churchill first used the term soon after the war, when the Soviet Union was beginning to carry out its plans for postwar dominance of eastern Europe.