element active in English word formation from mid-18c. and meaning "star or celestial body; outer space," from Greek astro-, stem and combining form of astron "star," which is related to aster "star," from PIE root *ster- (2) "star." In ancient Greek, aster typically was "a star" and astron mostly in plural, "the stars." In singular it mostly meant "Sirius" (the brightest star).
updated on October 09, 2017
Dictionary entries near astro-