An Etymological Dictionary of Astronomy and Astrophysics

The four largest and brightest satellites of → Jupiter, that is: → Io (Jupiter I), → Europa, → Ganymede, and → Callisto.

See also: Galileo, who had discovered them, called them Sidera Medicæa “Medicean Stars” in honor of the Medici family. → Galilean Moons; → satellite.