Same entry in other lexica; references at Photius pi181 Theodoridis. The headword -- either neuter nominative/accusative singular or masculine accusative singular of this superlative -- is evidently quoted from somewhere (perhaps Theocritus, Idylls 23.35, though there are other possibilities). For the glossing, cf. the scholia to Homer, Iliad 23.532, where the corresponding masculine nominative singular occurs (web address 1).