An Etymological Dictionary of Astronomy and Astrophysics

1. The rate at which a small object in free fall near the surface of a body is accelerated by the gravitational force of the body: g = GM / R², where G is the gravitational constant, and M and R are the mass and radius of the object. The
   surface gravity of Earth is equal to 980 cm s^-2.
   

2. → black hole surface gravity.

See also: → surface; → gravity.