Also see Sirius, and compare heliacal. The ancient Egyptian canicular year was computed from the heliacal rising of Sirius; the canicular cycle of 1,461 years is how long it would take a given day to pass through all seasons in an uncorrected calendar.
Proto-Indo-European root meaning "dog."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit svan-, Avestan spa, Greek kyōn, Latin canis, Old English hund, Old High German hunt, Old Irish cu, Welsh ci, Russian sobaka (apparently from an Iranian source such as Median spaka), Armenian shun, Lithuanian šuo "dog."
"pertaining to the sun" (but used especially of stars, in reference to their becoming visible out of the sun's glare), c. 1600, with -al (1) and Latinized form of Greek hēliakos "of the sun," from hēlios "sun" (from PIE root *sawel- "the sun"). The heliacal year (used in ancient Egypt) is reckoned from the heliacal rising of Sirius; thus it also is known as the canicular year. Related: Heliacally (1580s).