According to Greek mythology Medusa symbolizes female wisdom. Her wide unblinking eyes reflect her immense wisdom. They are all knowing, all seeing eyes that see through us, penetrating our illusions and looking into the abyss of truth.
Medusa also represents the Cycles of Nature as life, death and rebirth. She is universal Creativity and Destruction in eternal transformation.
Her mask was used to guard and protect women and the secret knowledge of the Divine Feminine. It literally warned men to "Keep Away! Female Mysteries." The serpent is a totem of the cycles of life, death and rebirth and the seasons. It is the connection to the fertile earth and to the underworld. It also symbolizes immortality as it was thought to shed its skin indefinitely. (A. La Van)

The Myth.
Medusa was one of the three sisters known as the Gorgons. Medusa was the only mortal out of the three. She was very beautiful ; her hair was her chief glory. She desecrated Athena’s temple by lying there with Poseidon. Outraged, Athena turned Medusa's hair into living snakes. Her gaze could turn whoever she looked upon to stone.. Perseus, approached Medusa while she slept, and taking care not to look directly at her, but guided by her image reflected in the bright shield which he bore, he cut off her head and gave it to Athena, who fixed it in the middle of her Aegis, which she wore over her breastplate.