Phaea was the name of the so-called Crommyonian Sow, the offspring of Typhon and Echidna. It ravaged the town of Crommyon, on the isthmus of Corinth, until Theseus killed it. Phaios means 'grey', 'dusky', which could refer to its colour.

On the other hand, Apollodorus tells us that the animal was actually owned by an old woman named Phaea. She in turn may have been so called since she was grey-haired. Either way, 'grey' suggests ghosts and the dead. It does not seem likely, as Robert Graves reads the name, that the origin is in phaos, 'light'.