The primary headword is genitive singular of the noun paiw/n, an alternative form of paia/n (i.e. the song/chant/hymn addressed to Apollo: see LSJ s.v. II and cf. pi 836, pi 837, pi 838, pi 841, pi 842, pi 884; also Hesychius s.v. w)=nac *paiw/n, Etymologicum Magnum s.v. paia/n.
*paia/n is also the ritual epithet of Apollo the healer (LSJ s.v. I 2), an independent god of healing (*paih/wn in Homer; Iliad 5.401 and 5.899 at web addresses 1 and 2), or, as appellative, a physician (LSJ s.v. I 3); cf. pi 876, pi 881, pi 882, pi 883; also ps.-Zonaras s.vv. paih/wn, paiw/neion, Photius s.vv. paiw=nas, paiwnei=on and Hesychius s.vv. paiw=nion, *pai/wn, paiw/nia and paiw/nion.