any barrier preventing the passage of ideas or understanding, especially an ideological, philosophical, or cultural barrier that divides countries, groups of people, or individuals: An iron curtain between theoreticians and creative artists prevented either group from appreciating the contributions of the other.

Example of the Iron Curtain Method An accountant incorrectly set up the depreciation calculation on a fixed asset five years ago. The annual impact of this error is $10,000, which is immaterial. However, under the iron curtain method, the error is material when the cumulative $50,000 impact of the error is considered.