Medusa, in Greek mythology one of three equally hideous-looking sisters (Gorgons). She and her sisters, Stheno and Euryale, had snakes growing from their heads in place of hair and fangs for teeth. Anyone looking directly at them turned to stone but Perseus slew Medusa by looking at a reflection of her as he cut off her head. Later he gave the head to Athena.
See also: Mythology.