ceraunia
From LSJ
Τὸ νικᾶν αὐτὸν αὑτὸν πασῶν νικῶν πρώτη τε καὶ ἀρίστη. Τὸ δὲ ἡττᾶσθαι αὐτὸν ὑφ' ἑαυτοῦ πάντων αἴσχιστόν τε ἅμα καὶ κάκιστον. → Τo conquer yourself is the first and best victory of all, while to be conquered by yourself is of all the most shameful as well as evil
Latin > English (Lewis & Short)
cĕraunĭa: v. ceronia.
Latin > French (Gaffiot 2016)
(1) cĕraunĭa, æ, f., pierre précieuse couleur de l’éclair : Plin. 37, 134.