I.hollow, excavated, concave (opp. plenus, full, round; class.).
I. Prop.: “cava conveniant plenis,” Lucr. 6, 1085: “cicutae,” id. 5, 1383: “tibia,” id. 2, 620: “concha,” Verg. A. 6, 171: “aes,” id. ib. 3, 240: “testudo,” id. G. 4, 464; Hor. Epod. 14, 11: “bucina,” Ov. M. 1, 335 et saep.: “ungula,” Enn. Ann. 419 Vahl.: “fornaces,” Lucr. 7, 202: “montes,” id. 5, 955: “specus,” Enn. Ann. 420 Vahl.: “cavernae,” Verg. A. 2, 53: “trabs,” id. ib. 3, 191 et saep.: “trunci,” Hor. C. 2, 19, 12: “ilex,” id. Epod. 16, 47: “saxa,” id. C. 3, 13, 14 et saep.: “vena,” the hollow vein, Cic. N. D. 2, 55, 138: “nubes,” Lucr. 6, 127; 6, 176; 6, 272; Verg. A. 1, 516; 5, 810 al.—Hence also of a darkness enveloping one as a cloud: “umbra,” Verg. A. 2, 360: “flumina,” the deepchannelled mountain streams, id. G. 1, 326; 4, 427; cf. Luc. 1, 396: luna, waning (cf. cavo), Plin. 8, 54, 80, § 215.—
B. Subst.: căvum , i, n. (access. form căvus , i, m. (sc. locus), Varr. R. R. 3, 15, 1; Hor. S. 2, 6, 116; id. Ep. 1, 7, 33; Phaedr. 4, 6, 3; Col. 12, 8), a hollow, cavity, hole, Cato, R. R. 128; Plaut. Men. 1, 2, 49; Lucr. 5, 1382; Liv. 24, 34, 9; Verg. G. 1, 184; Hor. S. 2, 3, 173; Plin. 2, 79, 81, § 192; 11, 51, 112, § 266 et saep.: “cava caeli,” Enn. Trag. 131 Vahl.; cf.: “cava caerula,” id. ib. 332 Vahl.; hence, căvum aedĭum (contr. căvae-dĭum , Phn. Ep. 2, 17, 5), the inner court of Roman houses (cf. Vitr. 6, 3 Schneid.; “O. Müll. Etrusk. 1, p. 255, and Archaeol. § 293, III.),” Varr. L. L. 5, § 161; Vitr. 6, 3; Dict. of Antiq.—
II. In late Lat., trop.: menses, which have only 30 days (opp. menses pleni, which have 31 days), Censor. 20.—