Glyph and Origin

Its glyph is a cross surmounting a curved stroke, read as a sickle or scythe. Saturn is the last of the seven classical planets known to Mesopotamian and Hellenistic astrology before the telescope. The kappa-rho ligature from which the sign derives had already worn down considerably by the Byzantine period: the twelfth-century compendium of Johannes Kamateros shows Saturn's glyph reduced to a shape close to the lower-case Greek letter eta, a stage between the original two-letter monogram and the cross-and-curve form used today, which suggests the sickle reading familiar from later astrological writing was applied only after the sign had already lost most of its legible connection to Kronos's Greek initials, a pattern of a letterform gradually resolving into an independent picture that recurs, to varying degrees, across most of the classical seven and is simply better documented for Saturn than for some of its companions because Kamateros's compendium happens to preserve this particular intermediate stage.

Along with the rest of the classical seven, Saturn's sign was fixed in digital typography when Unicode encoded the full set of astrological and astronomical glyphs in the Miscellaneous Symbols block of its 1991 release, closing a gap of roughly two thousand years between the sign's origin as a scribal abbreviation and its modern life as a single stable character.