halo in WordNet English dictionary

1. a toroidal shape
   "a ring of ships in the harbor"; "a halo of smoke"
   ring  halo  annulus  doughnut  anchor ring 
   
2. an indication of radiant light drawn around the head of a saint
   aura  aureole  halo  nimbus  glory  gloriole 
   
3. a circle of light around the sun or moon
   halo