The headword is an unaugmented epic aorist, third person singular, of kai/w; from *kaw-sa > kāwa > (Ionic) kh=a, it would be better spelled without the iota subscript. The form occurs once in Homer, at Iliad 21.349 (web address 1), and otherwise only in commentary on this verse. The augmented form e)/khe does occur, however. The gloss is the regular imperfect of the same verb.
For kai/w (from *kaw-yō), see also kappa 1184, kappa 1185.