I.clearness, serenity.
I. Lit., of the weather, clear, fair, or serene weather; with gen.: cum sit tum serenitas, tum perturbatio caeli, * Cic. Div. 2, 45, 94: “diei solisque, Auct. B. Hisp. 29, 4: auctumni,” Plin. 18, 35, 80, § 353.— Absol.: “tranquilla serenitas (opp. foeda tempestas),” Liv. 2, 62, 2; 2, 26, 11: “serenitatem praesagire,” Plin. 18, 35, 87, § 362; 10, 67, 86, § 188.—Plur.: “(vinea) imbribus magis quam serenitatibus offenditur,” Col. 3, 1, 10.—
II. Trop.
1. Fairness, serenity of fortune, of disposition, etc. (rare; “perh. not ante-Aug.): praesentis fortunae,” Liv. 42, 62, 4: “minor es, quam ut serenitatem meam obducas,” Sen. Ira, 3, 25, 4: “quantam tempestatem subitā serenitate discussit (principis ortus),” Curt. 10, 9, 5.—
2. Serenitas, a title of the Roman emperors, = Serene Highness, Veg. Mil. 3 epil.; Inscr. Grut. 286, 2.