A Cold War metaphor
for the military
and political boundaries
between the Soviet bloc nation
s and the rest of Europe
Winston Churchill brought this phrase into the English language in a speech he gave less than one year after the end of World War II, on March 5, 1946.
"From Stettin in the Baltic to Trieste in the Adriatic, an iron curtain has descended across the continent," Churchill said. Later, a more literal curtain would rise -- and fall -- in the form of the Berlin Wall.
The phrase 'iron curtain' has remained a part of English for over fifty years. While it is occasionally used in other circumstances, it is most often used to refer to the communist countries of Europe during the Cold War.
Props to Rook for the correct quote!