Gr. Myth. sister of Philomela and wife of Tereus, transformed into a swallow by the gods
See Procne in American Heritage Dictionary 4
(prŏkˈnē)
noun Greek Mythology
An Athenian princess who avenged the betrayal and cruelty of her husband, Tereus, by killing their son. She and her sister Philomela were changed into swallows as Tereus pursued them.