Definition of astro- in English:

astro-

combining form

  • Relating to the stars, celestial objects, or outer space.

    ‘astrophotography’
    ‘astrocompass’
    ‘astrophysics’
    ‘astrochemistry’

Origin

From Greek astron ‘star’.

Pronunciation

astro-

/ˈastrō//ˈæstroʊ/