heliac Meaning, Definition & Usage

1. adjective pertaining to or near the sun; especially the first rising of a star after and last setting before its invisibility owing to its conjunction with the sun
   heliacal.
   
   • the heliacal rising of the Dog Star
   • the heliacal or Sothic year is determined by the heliacal rising of Sothis (the Egyptian name for the Dog Star)

WordNet