heliacal adj.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).

*sāwel-, Proto-Indo-European root meaning "the sun." According to Watkins, the *-el- in it originally was a suffix, and there was an alternative form *s(u)wen-, with suffix *-en-, hence the two forms represented by Latin sol, English sun.

It forms all or part of: anthelion; aphelion; girasole; heliacal; helio-; heliotrope; helium; insolate; insolation; parasol; parhelion; perihelion; Sol; solar; solarium; solstice; south; southern; sun; Sunday.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit suryah, Avestan hvar "sun, light, heavens;" Greek hēlios; Latin sol "the sun, sunlight;" Lithuanian saulė, Old Church Slavonic slunice; Gothic sauil, Old English sol "sun;" Old English swegl "sky, heavens, the sun;" Welsh haul, Old Cornish heuul, Breton heol "sun;" Old Irish suil "eye;" Avestan xueng "sun;" Old Irish fur-sunnud "lighting up;" Old English sunne German Sonne, Gothic sunno "the sun."

late 14c., in caniculer dayes, the "dog days" around mid-August, from Latin canicularis "pertaining to the dog days or the Dog Star (Sirius)," from canicula "little dog," also "the Dog Star," diminutive of canis "a dog" (from PIE root *kwon- "dog"). Historically, it is attested in literal use ("pertaining to a dog") only in jocular humor.

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.