βροντηδόν
From LSJ
ὀφθαλμοὶ γὰρ τῶν ὤτων ἀκριβέστεροι μάρτυρες → the eyes are more accurate witnesses than the ears, the eyes are more exact witnesses than the ears
German (Pape)
[Seite 464] donnerartig, Or. Sib.
Greek (Liddell-Scott)
βροντηδόν: ἐπίρρ., ὡς βροντή, Χρησμ. Σιβύλλ. 5345.
Spanish (DGE)
adv. como un trueno ἔσται ... β. κελάδημα Orac.Sib.5.345.