1. ( sometimes caps. ) a barrier to understanding and the exchange of information and ideas created by ideological, political, and military hostility of one country toward another, esp. such a barrier between the Soviet Union and its allies and other countries.
2. an impenetrable barrier to communication or information, esp. as imposed by rigid censorship and secrecy.
[ used by Winston Churchill in 1946 to describe the line of demarcation between Western Europe and the Soviet zone of influence ]