astro-

1. a combining form with the meaning “pertaining to stars or celestial bodies, or to activities, as spaceflight, taking place outside the earth's atmosphere,” used in the formation of compound words:

   astronautics; astrophotography.

astro-

combining_form

1. indicating a heavenly body, star, or star-shaped structure

   astrocyte

   astrology

2. indicating outer space

   astronautics

astro–

1. A prefix that means “star” (as in astrophysics ), “celestial body” (as in astronomy ), or “outer space” (as in astronaut ).

Word History and Origins

Origin of astro-¹

< Greek, combining form of ástron a star, constellation, akin to astḗr star; aster, -aster ²

Word History and Origins

Origin of astro-¹

from Greek, from astron star