|1.||indicating a heavenly body, star, or star-shaped structure: astrology; astrocyte|
|2.||indicating outer space: astronautics|
|[from Greek, from astron star]|
|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a chattering or flighty, light-headed person.|
A prefix that means "star" (as in astrophysics), "celestial body" (as in astronomy), or "outer space" (as in astronaut).