sĕrēnus, a, um, adj. [Sanscr. svar, sky; Gr. Σείριος; cf. σέλας; Lat. sol], clear, fair, bright, serene (class.; esp. freq. in the poets; cf. sudus).
I Lit.: cum tonuit laevum bene tempestate serenā, Enn. ap. Cic. Div. 2, 39, 82 (Ann. v. 517 Vahl.): caelo sereno, Lucr. 6, 247; Cic. Fam. 16, 9, 2; Verg. G. 1, 260; 1, 487; id. A. 3, 518; Hor. Epod. 15, 1; id. S. 2, 4, 51; Ov. M. 1, 168; 2, 321 et saep.; cf.: de parte caeli, Lucr. 6, 99: in regione caeli, Verg. A. 8, 528.— Comp. : caelo perfruitur sereniore, Mart. 4, 64, 6; cf. also: o nimium caelo et pelago confise sereno, Verg. A. 5, 870: postquam ex tam turbido die serena et tranquilla lux rediit, Liv. 1, 16, 2: luce, Verg. A. 5, 104: lumen (solis), Lucr. 2, 150: nox, id. 1, 142; Cic. Rep. 1, 15, 23; Verg. G. 1, 426: sidera, Lucr. 4, 212: facies diei, Phaedr. 4, 16, 5: species mundi, Lucr. 4, 134: aër, Plin. 17, 24, 37, § 222: ver, Verg. G. 1, 340: aestas, id. A. 6, 707: stella, Ov. F. 6, 718 et saep.: color (opp. nubilus), bright , clear , Plin. 9, 35, 54, § 107: aqua (with candida), Mart. 6, 42, 19: vox, Pers. 1, 19.—Transf., of a wind that clears the sky , that brings fair weather : hic Favonius serenu'st, istic Auster imbricus, * Plaut. Merc. 5, 2, 35; hence, also, poet.: unde serenas Ventus agat nubes, Verg. G. 1, 461.—
2 As subst.: sĕrēnum , i, n., a clear , bright , or serene sky , fair weather (not in Cic.): ponito pocillum in sereno noctu, during a fine night , Cato R. R. 156, 3; more freq. simply sereno: Priverni sereno per diem totum rubrum solem fuisse, Liv. 31, 12, 5; 37, 3, 2: quare et sereno tonat, Sen. Q. N. 2, 18; Plin. 11, 24, 28, § 84 (opp. nubilo), Pall. 1, 30, 3; Luc. 1, 530: liquido ac puro sereno, Suet. Aug. 95: nitido sereno, Sil. 5, 58: cottidie serenum cum est, Varr. R. R. 3, 10, 4: laesique fides reditura sereni, Stat. S. 3, 1, 81: serenum nitidum micat, Mart. 6, 42, 8.— Plur. : caeli serena Concutiat sonitu, Lucr. 2, 1100: soles et aperta serena, Verg. G. 1, 393: nostra, Val. Fl. 1, 332.—
II Trop.
1 Cheerful , glad , joyous , tranquil , serene (syn.: laetus, tranquillus, secundus): vita, Lucr. 2, 1094 Lachm.: horae (with albus dies), Sil. 15, 53: rebus serenis servare modum, in propitious or favorable circumstances , in good fortune , id. 8, 546: vultus, Lucr. 3, 293; Cat. 55, 8; Hor. C. 1, 37, 26; Ov. Tr. 1, 5, 27: frons tranquilla et serena, Cic. Tusc. 3, 15, 31: pectora processu facta serena tuo, Ov. Tr. 1, 9, 40: animus, id. ib. 1, 1, 39: oculi, Sil. 7, 461: Augustus, Ov. P. 2, 2, 65: laetitia, Just. 44, 2, 4: imperium, Sil. 14, 80: res, id. 8, 546: sereno vitae tempore, Auct. Her. 4, 48, 61: vita, Lucr. 2, 1094: temperatus (sanguis) medium quoddam serenum efficit, Quint. 11, 3, 78; cf.: tandem aliquid, pulsā curarum nube serenum Vidi, Ov. P. 2, 1, 5.—
2 SERENVS, an epithet of Jupiter (whose brow was always serene), Inscr. Murat. 1978, 5; cf. Serenator; hence, Martial calls Domitian: Jovem serenum, Mart. 5, 6, 9; 9, 25, 3.—
3 Serenissimus, a title of the Roman emperors , Cod. Just. 5, 4, 23.