What does mcm means in cable?

In the context of cable, "MCM" stands for "thousand circular mils," which is a unit of measurement used to describe the cross-sectional area of electrical conductors. One MCM equals 1,000 circular mils, where a circular mil is the area of a circle with a diameter of one mil (one-thousandth of an inch). This measurement helps in determining the current-carrying capacity and resistance of the cable. MCM is commonly used in the United States for large conductors, especially in industrial and commercial applications.