☙

circular mil

A unit of area, the area of a circle with a diameter of 1 mil (1/1000th of an inch). Thus = pi × the square of 1/2000 inches, about 7.85398 × 10⁻⁷ square inches (5.06707 × 10⁻⁴ square millimeters). Its principal use is in describing the cross-sectional area of electric conductors. The sizes of cables larger than one inch in diameter are usually given in circular mils, not gauge numbers.