An Etymological Dictionary of Astronomy and Astrophysics

The → gravitational attraction of a system of masses, such of a planet, that allows the system to be held together by their mutual gravity.
Self-gravity between atoms allows a → star to hold together, despite tremendous temperature and pressure. Similarly, to be considered a → planet, a body must have enough mass so that its self-gravity pulls it into a near-spherical shape.

See also: → self-; → gravity.