The glosses, especially the second of them, show that the headword is being construed as feminine accusative singular of this adjective. (For an alternative feminine form of pi/wn, see pi 1566.) Likewise or similarly in other lexica (references at Photius pi891 Theodoridis), and cf. also a scholion on Homer, Iliad 1.40, where however pi/ona is the neuter accusative plural (web address 1).