Same entry in other lexica. The headword is third person plural, imperfect indicative middle, of the verb ei)sxe/w. It must be quoted from somewhere: the possibilities include Josephus, Jewish Antiquities 14.69, for the headword in this exact form, but Theodoridis on Photius s.v. notes Dindorf's suggestion that it is is actually e)sexe/onto from Herodotus 9.70.2.