[1] Likewise in other lexica, including Timaeus' Platonic Lexicon. That work does not confine itself to Plato, however, so there is no call to doubt the assertion in (e.g.) Philoxenus and the Lexicon Vindobonense that dia/sfac is extracted from Herodotus (7.199).
2From glosses on Herodotus 3.117.1 (web address 1), where this nominative plural occurs.