Short answers, pulled from the story.
A harpy is a half-human, half-bird creature from Greek and Roman mythology, originally believed to personify the destructive nature of storm winds. The name means "snatchers" or "swift robbers." They appear in Homeric poems and in the works of Hesiod, Virgil, Aeschylus, and Ovid, among others.
The name comes from the Greek harpyia, meaning "snatcher" or "swift robber." It reflects the harpies' role in myth: stealing food from victims mid-meal and carrying evildoers away to be punished by the Erinyes.
Hesiod named two harpies: Aello, meaning "storm swift," and Okypete, meaning "the swift wing." Virgil added a third, Celaeno, meaning "the dark." Homer named a fourth, Podarge, meaning "fleet-foot," who was said to be the mother of Achilles' immortal horses Balius and Xanthus, fathered by the West Wind Zephyrus.
Zeus blinded King Phineus of Thrace and condemned him to a feast he could never eat, because harpies stole or fouled every meal. Jason and the Argonauts freed him by sending the Boreads, Zetes and Calais, to drive the harpies away; Phineus in return guided the Argonauts safely past the Symplegades.
Descriptions varied widely across ancient sources. Hesiod saw them as lovely-haired winged maidens; Virgil described bird-bodied, girl-faced creatures with talons and faces haggard with insatiable hunger; Hyginus gave them cocks' heads, human arms, and great claws; pottery art showed beautiful winged women; Ovid described them as human-vultures.
Dante placed harpies in the seventh ring of Hell in the 13th Canto of his Inferno, inspiring William Blake's painting The Wood of the Self-Murderers: The Harpies and the Suicides, now at the Tate Gallery in London. Ludovico Ariosto adapted the Phineus story in Canto XXXIII of Orlando Furioso, and Shakespeare featured harpies in both The Tempest and Much Ado About Nothing.