«Железный занавес»: От технического термина до политической метафоры

The history of formation of the set expression «iron curtain» in Russian language is considered in the article. It appeared more than 200 years ago and at first it was used in its direct terminological meaning. The metaphorical meaning in the political context this expression acquires (both in European languages and Russian language) in the first decades of XX century. The question about authorship of this expression in its new meaning is disputable still.