ἐπίσωτρον
From LSJ
Dante Alighieri, Paradiso, XXXIII, v. 145
English (LSJ)
Poll.1.144, Hsch., Ep. ἐπίσσωτρον (as always in Hom.), τό,
A metal hoop upon the felloe (σῶτρον), tire of a wheel, Il.23.519: mostly in pl., 5.725, 11.537, al.:—ὀπίσσωτρον is v.l. in Hom. and Hsch.