The glyph is an M-like figure closed by a crossed loop, conventionally read as a stylised maiden, and the closed loop that distinguishes it from the very similar Scorpio glyph is often explained as a sealed or self-contained womb, though that reading is symbolic rather than something any ancient writer actually documents.
The sign is part of the Babylonian zodiac transmitted through Hellenistic astrology, and its maiden has been identified at different times with Demeter, goddess of the grain harvest she is often shown carrying, with Astraea, the last of the gods said to abandon a corrupted earth, and with a Mesopotamian goddess of the furrow, an identification that reaches back to Babylonian sky lore well before the Greek maiden was attached to the same stars.
The written form is preserved through Byzantine copies of Greek horoscopes, the manuscript corpus catalogued by Otto Neugebauer and Henry Van Hoesen, and only reached a settled printed shape in the fifteenth and sixteenth centuries, after printers working in the tradition of Regiomontanus's early Nuremberg Kalendarium and Ephemerides began setting the sign consistently in type. Through precession, the slow wobble of the Earth's axis, it has drifted from the constellation Virgo over the more than two millennia since the sign was first fixed.