- pertaining to or occurring near the sun, especially applied to such risings and settings of a star as are most nearly coincident with those of the sun while yet visible.
Also he·li·ac [hee-lee-ak] /ˈhi liˌæk/.
Origin of heliacal
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for heliacal
He must mean either the heliacal or achronical rising of that sign.Discourses on Satire and on Epic Poetry
They also possessed lists of the fixed stars, and drew up tables of the times of their heliacal risings.The Babylonian Legends of the Creation
Swart star: the Dogstar, called swarthy because its heliacal rising in ancient times occurred soon after mid-summer.The Golden Treasury
This was based upon the heliacal rising of Sirius (Sothis) coincident with the beginning of the inundation.
Implying hereby the Heliacal ascent and Cosmical descent of those stars.The Works of Sir Thomas Browne (Volume 2 of 3)
Word Origin and History for heliacal
Online Etymology Dictionary, © 2010 Douglas Harper