Lewis & Short

1. sĕnectus, a, um, adj. [senex], aged, very old.

  1. I. Adj. (rare, and mostly anteclass.): senecta aetas, Plaut. Am. 4, 2, 12; id. Trin. 1, 2, 5; id. Aul. 2, 2, 75; id. Cas. 2, 3, 23; 2, 3, 41; id. Merc. 5, 4, 25; Lucr. 5, 886; 5, 896; Sall. Fragm. ap. Serv. Verg. A. 11, 165: membris exire senectis, Lucr. 3, 772: corpus, Sall. ap. Prisc. p. 869 (H. 4, 63 Dietsch): aetas, id. ap. Serv. Verg. A. 11, 165 (H. inc. lib. 115 Dietsch).
  2. II. Subst.: sĕ-necta, ae, f., old age, extreme age, senility (freq., though mostly poet. and in post-Aug. prose; not in Cic.; cf. 2. senectus).
    1. A. In abstr.: prospiciendum ergo in senectā: nunc adulescentia est, Lucil. ap. Non. 492, 23; Enn. ap. Cic. Or. 55, 184 (Trag. v. 393 Vahl.; v. Vahl. N. cr. ad h. 1.); Plaut. Most. 1, 3, 60 (opp. aetatula); id. Trin. 2, 3, 7; id. Mil. 3, 1, 29; * Ter. Ad. 5, 8, 31; Caecil. ap. Cic. Sen. 8, 25; Lucr. 4, 1256; Liv. 2, 40, 6; 6, 8, 2; 24, 4, 2; 28, 16, 12; 38, 53, 9; Cat. 64, 217; Tib. 1, 4, 31; 1, 8, 42; 1, 10, 40 al.; Prop. 1, 19, 17; 2, 13 (3, 5), 47; 3, 5 (4, 4), 24; 3, 19 (4, 18), 15; Verg. G. 1, 186; 3, 96; id. A. 6, 114 al.; Hor. C. 1, 31, 19; 2, 6, 6; 2, 14, 3; id. Ep. 2, 2, 211; Ov. M. 3, 347; 6, 37; 6, 500; 6, 675 et saep. al.: in senectā, Varr. L. L. 5, § 5 Müll.; so in prose, Petr. 132, 10; Plin. 7, 50, 51, § 167; 8, 32, 50, § 116; 16, 27, 51, § 117 et saep.; Tac. A. 3, 23; 3, 55; 4, 41; 4, 58 fin.; 13, 33; 14, 65 al.; Suet. Aug. 79; id. Ner. 40; id. Galb. 4, 17; id. Gram. 11; Vulg. Psa. 70, 18 al.
    2. B. In the elder Pliny, concr. ( = 2. senectus, II.), the old skin, slough of a serpent, cast off annually: serpentes senectam exuendo, etc., Plin. 20, 23, 95, § 254; 28, 11, 48, § 174; 30, 8, 22, § 69.
    3. C. An old man, Sil. 8, 6; cf. id. 7, 178.