An Etymological Dictionary of Astronomy and Astrophysics

1. The physical situation reached in a fluid when complete balance exists between the internal pressure at any point and the weight of the material above the point.
   

2. For a star, the balance between the inward → gravitational force and the outward gas pressure everywhere in the star. → hydrostatic equation. See also → hydrodynamic equilibrium.

See also: → hydrostatic; → equilibrium.