An Etymological Dictionary of Astronomy and Astrophysics

1. Meteo.: Rings or arcs that seem to encircle the sun or moon and are the result of the refraction of light through the ice crystals that make up cirrus clouds.
   

2. → halo of galaxy.

Etymology (EN): Halo, from L. (acc.) halo, from Gk. halos “ring of light around the sun or moon.”

Etymology (PE): Hâlé, loanword from Ar.