The headword is an epic aorist active of καίω , third person plural, glossed by the equivalent Attic form. Cf. scholion on Homer, Iliad 1.40, where the first person singular occurs.
The root is *καf- : in the aorist *καf-σα- produced *κā-fα- , and in Ionic κη-α- . Other forms of this verb appear at kappa 1184, kappa 1185.