1. (mineralogy) a star-shaped figure with six rays that is seen in some crystal structures under reflected or transmitted light
   "The gemologist observed an asterism in the sapphire"
    
2. (astronomy) a cluster of stars (or a small constellation)
   "The Big Dipper is a well-known asterism within the constellation Ursa Major"

Derived forms: asterisms

Type of: natural object, star

Part of: constellation

Encyclopedia: Asterism