What key concept does the phrase "Iron Curtain" refer to in Cold War history?

The phrase "Iron Curtain" is primarily used to describe the political and ideological boundary that separated communist nations in Eastern Europe from democratic nations in Western Europe during the Cold War. Coined by Winston Churchill in a speech in 1946, it symbolizes the drastic divide between the Soviet-controlled countries and those aligned with the West. This division was not only geographical but also reflected differing political systems, economic structures, and cultural ideologies. The Iron Curtain became a defining metaphor for the Cold War period, representing the tensions and hostilities that characterized the relationship between the Soviet Union and the Western allies. Thus, the significance of this term lies in its encapsulation of the broader conflict and competition between communism and democracy during the mid-20th century.