The headword (which must be quoted from somewhere) is third person singular, present middle/passive, of (it would seem) a verb lai/w. The main LSJ entry (web address 1) summarily presents such a verb as the equivalent of la/w ('I seize'), citing the Cyrilli Glossarium. The Supplement adds: 'II. l. to\ ble/pw h)\ to\ foneu/sw, Theognost. Can. 27A. III. lai/etai: kataleu/etai, Hsch'.
Ps.-Zonaras 1290 has the same gloss as the present one, but is too late (C13) to be an independent witness. Theognostos is earlier (C9), but complicates the issue by glossing lai/etai (with klu/etai 'is heard') shortly before the glosses on lai/w. It seems that these Byzantine scholars did not really know the form or the provenance or the meaning of lai/etai, and without a context, neither do we.