lăcūna (collateral form lŭcūna; cf. Lachm. ad Lucr. vol. 2, p. 205; lăcūnā-tūra, App. Flor. 15, p. 351, 2 Hildebrand; v. infra), ae, f. lacus, a ditch, pit, hole; esp. a place where water collects, a pool, pond. Lit. (mostly poet.): lacuna, id est aquae collectio, a lacu derivatur, quam alii lamam, alii lustrum dicunt, Paul. ex Fest. p. 117 Müll.: vastae, Lucr. 6, 552: vastae Orci, id. 1, 116; 6, 538: cavae, Verg. G. 1, 117; 3, 365.—Poet.: salsae, i. e. the sea, Lucr. 5, 794; 3, 1044; also, Neptuniae, Auct. Her. 4, 10, 15: caecas lustravit luce lacunas, Cic. Arat. 431.— In gen., a hollow, cavity, opening, chasm, cleft: cum supercilia cana, et sub ea lacunae, dicunt, eum equum habere annos sedecim, Varr. R. R. 2, 7, 3; 1, 29, 3; cf.: atque lacunarum fuerant vestigia cuique, Lucr. 5, 1261; Vitr. 7, 1, 4: labrum superius sub ipsa medietate narium lacuna quadam levi, quasi valle, signavit deus, Lact. Op. D. 10: genae teretes ac medio mento lacuna, a dimple, App. Flor. p. 351 (Hildebr., lacunatura).— Trop., a gap, void, defect, want, loss (rare but class.): est, qui expleas duplicem istam lacunam, to fill up the double void, Varr. R. R. 2, 1, 28: ut illam lacunam rei familiaris expleant, Cic. Verr. 2, 2, 55, § 138: lacuna in auro, id. Att. 12, 6, 1: illa labes et quasi lacuna famae, Gell. 1, 3, 23.