What did the term "Iron Curtain" refer to during the Cold War?

The term "Iron Curtain" specifically referred to the ideological and physical division that emerged in post-World War II Europe, distinguishing the communist countries of Eastern Europe from the capitalist nations of Western Europe. This metaphor was famously popularized by British Prime Minister Winston Churchill in his 1946 speech, in which he highlighted how the Iron Curtain represented a boundary that was not easily crossed, both politically and militarily. The Iron Curtain symbolized the tensions and conflicts of the Cold War era, serving as a vivid representation of the struggle between the two opposing ideological blocs: communism and capitalism. This division facilitated the development of separate economic systems, governance, and social structures throughout those regions, significantly shaping the geopolitical landscape of the 20th century.