Glyph and Origin

Its glyph is a circle with a central dot, an ancient sign for the solar disc. The Sun is one of the seven classical planets observed and personified as deities in Mesopotamia and codified as astrological bodies in the Hellenistic Greek world. The precise circumpunct shape used today is not the oldest attested form: Byzantine sources such as the twelfth-century astronomical compendium of Johannes Kamateros instead show the Sun as a plain circle with a single radiating line, closer to a child's drawing of a sunburst than to the dotted disc familiar from modern ephemerides. The enclosed dot appears to be a later refinement, generally dated to the Renaissance, and has been read as a schematic version of Apollo's golden shield with its central boss, though no ancient source confirms the reading and it remains conjecture rather than established fact.

Along with the other six classical planets, the Sun's sign entered the earliest version of computerised text encoding when Unicode fixed it, together with the full set of planetary and zodiacal glyphs, in the Miscellaneous Symbols block introduced in Unicode's original 1991 release, carrying a symbol with a documented history of well over a thousand years into ordinary digital typography.