Same entry in Hesychius, ps.-Zonaras, and (according to Adler) the Ambrosian Lexicon.
In the Greek, headword and gloss, both neuter nouns, differ simply in their prepositional prefix. For the (rare) headword, routinely glossed thus in lexicography, see e.g. Marcus Aurelius, Meditations 10.33.3. For the (commonplace) gloss cf. pi 2737.