a. A unit employed in the gravitational method of geophysical prospecting.
It is about one millionth of the average value of the acceleration due to
gravity at the Earth's surface; i.e., 1 milligal = 1 cm/s2 .
Nelson b. A unit of acceleration used with gravity measurements; 10-3
Gal = 10-5 m/s2 . Abbrev: mGal. AGI
Dictionary of Mining, Mineral, and Related Terms