Its glyph is a circle above a cross, traditionally described as a hand mirror. The same sign was later taken up in the biological sciences as the standard mark for the female sex. Venus is one of the seven classical planets of ancient Mesopotamian and Hellenistic astrology. In alchemy the identical sign stood for copper, a metal prized since antiquity for the fine mirrors and ornaments made from it, which may be part of why the hand-mirror reading of the astrological glyph took hold so readily among later commentators, even though no ancient source directly explains the design.
The Romance-language weekday descended from the planet, vendredi in French, venerdi in Italian, preserves the Latin dies Veneris, Venus's day, while English Friday instead carries the name of the Germanic goddess Frigg, substituted for Venus in the same wave of interpretatio germanica that gave Wednesday to Woden in place of Mercury.
Venus's glyph entered the Unicode standard with the rest of the classical planetary set in the Miscellaneous Symbols block of its 1991 release, and it is separately encoded again as the plain "female sign" used in ordinary typography. That second, purely typographic encoding is now by far the sign's most common use worldwide, on restroom doors and official forms, so that most people who read the mark today have never connected it to Venus, the goddess, the metal or the weekday at all.