Adjective has 1 sense

• heliac(a = adj.pert) heliacal - 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; "the heliacal or Sothic year is determined by the heliacal rising of Sothis (the Egyptian name for the Dog Star)"; "the heliacal rising of the Dog Star"