ἔξαψις σφοδρὰ μετὰ πολλῆς βίας πίπτουσα ἐπὶ γῆς → a violent flare-up falling on the ground with great force, thunder and lightning
dĭoptra: ae, f., = δίοπτρα,
I an optical instrument to measure the height of places, Vitr. 8, 6; for measuring the sun's shadow, Plin. 2, 69, 69, § 176.