I. Lit.: ea, quae ille (Epicurus) propter firmitatem stere/mnia appellat, Cic. N. D. 1, 19, 49: age specta, postes cujusmodi! Quanta firmitate facti, Plaut. Most. 3, 2, 134: materiae, Caes. B. C. 2, 11, 1: amphorarum, Plin. 35, 12, 46, 161: Aegyptii lini, id. 19, 1, 2, 14: fastigiorum templorum, id. 35, 12, 46, 158: uvae contra frigora, etc., id. 14, 3, 4, 40: vini, id. 14, 2, 4, 21: gladiatoria totius corporis, vigor, Cic. Phil. 2, 25, 63; cf. Quint. 8, 4, 16: corporis, id. 11, 3, 19; 2, 16, 13; Plin. Pan. 4, 7; 15, 1: capitis, lateris pecorisve, Quint. 11, 3, 16; 40: firmitas et vigor vocis, Gell. 2, 3, 4: valetudinis, Plin. 20, 5, 20, 42. —In plur.: pulvis Puteolanus aedificiis praestat firmitates, Vitr. 2, 6.—

II. Trop., firmness, steadfastness, stability, endurance, constancy, power: firmitas et constantia, Cic. Fam. 9, 11, 1: animi, id. Sest. 44, 95; id. Att. 12, 38, 3; id. Tusc. 5, 26, 74: sapientis, id. Ac. 2, 20, 66: exercitus numero amplissimus, firmitate exiguus, Planc. in Cic. Fam. 10, 24, 3: ut quisque minimum firmitatis haberet minimumque virium, ita amicitias appetere maxime, Cic. Lael. 13, 46; cf.: ea (amicitia) non satis habet firmitatis, id. ib. 5, 19: si aliquid firmitatis nactus sit Antonius, id. Fam. 11, 12, 1: imperii, Suet. Vesp. 7.