laetum

From LSJ

ἔξαψις σφοδρὰ μετὰ πολλῆς βίας πίπτουσα ἐπὶ γῆς → a violent flare-up falling on the ground with great force, thunder and lightning

Source

Latin > French (Gaffiot 2016)

lætum, n. pris advt, d’une manière gaie : Stat. Ach. 1, 323.