An Etymological Dictionary of Astronomy and Astrophysics

A star that lies within the → galactic disk of a → spiral galaxy.
Stars belonging to the → thin disk, such as the Sun or Alpha Centauri, lie at a typical distance of about 1,000 → light-years from the galactic midplane. There are also → thick disk stars, such as Lalande 21185, that lie at an average distance of about 3,500 light-years from the midplane.

See also: → disk; → star.