Word Study
astro-
CIDE DICTIONARY
astro-,
The combining form of the Greek word 'a`stron , meaning star . [1913 Webster]
OXFORD DICTIONARY
astro-, comb. form 1 relating to the stars or celestial bodies.
2 relating to outer space.
2 relating to outer space.
Etymology
Gk f. astron star
For further exploring for "astro-" in Webster Dictionary Online