Paeon (or Paean) was a physician of the gods, and subsequently one of the by-names of Apollo. Homer mentions him as curing Hades when he was wounded by one of Heracles' arrows as he defended the entrance to the Underworld. His name has the same origin as that of Paeonius, that is, 'healer', from paio, 'to strike', 'drive away'.

As a by-name of Apollo, Paeon (or Paean) was transferred to songs dedicated to him and to other gods, itself ultimately becoming the word for a battle, victory or festive song - a 'paean', in fact. The same name can also be seen in the peony (or paeony), a flower that used to be favourably regarded for its medicinal properties.