I.Abl. plur. never found; “acc. to the gram., Don. p. 1751,” Diom. p. 285, Prisc. p. 779, Rhem. Palaem. p. 1371 P. al., it was arcubus; so Vulg. 2 Esdr. 4, 13; cf. Rudd. I. p. 104, n. 48.—Gen. sing. arqui, Lucr. 6, 526 Lachm., and Cic. N. D. 3, 20, 51 B. and K.—Dat. arcu, Sil. 4, 18.—Nom. plur. ARCVVS, Corp. Inscr. V. 85; Inscr. Henz. 5313: arci, Varr. ap. Non. p. 77, 12.—Acc. ARCOS, Corp. Inscr. II. 3420.—Fem., Enn. ap. Prisc. p. 712 P.; cf. id. 658 P.; and Serv. ad Verg. 6, 610, says that Catull. and others used it as fem.; v. Neue, Formenl. I. p. 679) [cf. Sanscr. arālas = bent, the bent arm, aratnis = Gr. ὠλένη; Lat. ulna; Germ. Elbogen; Engl. elbow. Curt.], prop., something bent; hence,
I. A bow (syn. cornu).
A. For shooting: intendit crinitus Apollo Arcum auratum, Enn. ap. Cic. Ac. 2, 28, 89 (Trag. v. 54 Müll.): “arcus intentus in aliquem,” Cic. Sest. 7: “haec cernens arcum intendebat Apollo Desuper,” Verg. A. 8, 704; 9, 665; so Vulg. Psa. 10, 3; 36, 14: “arcum tendere,” ib. 3 Reg. 22, 34; ib. 4 Reg. 9, 24: “adductus,” Verg. A. 5, 507: “remissus,” Hor. C. 3, 27, 67: “arcum dirigere in aliquem,” Pers. 3, 60: “quom arcum et pharetram mi et sagittas sumpsero,” Plaut. Trin. 3, 2, 98; so, “arcum suscitare,” Vulg. Hab. 3, 9 et saep. —
B. The rainbow (fully: pluvius arcus, v. infra, II.), Enn. ap. Prisc. p. 712 P. (Ann. v. 393 Vahl.): Tum color in nigris existit nubibus arqui, * Lucr. 6, 526 Lachm.: “arcus ipse ex nubibus efficitur quodam modo coloratis,” Cic. N. D. 3, 20, 51: “ceu nubibus arcus Mille jacit varios adverso sole colores,” Verg. A. 5, 88 Rib.; so Ov. M. 6, 63; 11, 632; 14, 838: “pluvius describitur arcus,” Hor. A. P. 18; Liv. 30, 2; 41, 21; Plin. 18, 35, 80, § 353; Sen. Q. N. 1, 5 and 6: “arcum meum ponam in nubibus,” Vulg. Gen. 9, 13 sqq. (in Vulg. Apoc. 4, 3; 10, 1, iris, q. v.) al.—
C. A bow or arch in building, a vault, arch, triumphal arch, etc.: “efficiens humilem lapidum compagibus arcum,” Ov. M. 3, 30; 3, 160; Juv. 3, 11; Suet. Ner. 25: “marmoreus arcus,” id. Claud. 1; so id. ib. 11; id. Dom. 13; cf. Plin. Pan. 59, 2 Schwarz.—
II. Transf.
A. Poet. or in post-Aug. prose, any thing arched or curved like a bow; of the breaking of waves: “niger arcus aquarum,” Ov. M. 11, 568.—Of the windings of a serpent: “immensos saltu sinuatur in arcus,” Ov. M. 3, 42.—Of a curve in flight: “dea se paribus per cælum sustulit alis Ingentemque fugā secuit sub nubibus arcum,” Verg. A. 5, 658.—Of the curving or bendings of a bay: “sinus curvos falcatus in arcus,” Ov. M. 11, 229 (cf.: “inque sinus scindit sese unda reductos,” Verg. A. 1, 161).— “Of a harbor: Portus ab Euroo fluctu curvatus in arcum,” Verg. A. 3, 533.—Of boughs of trees, Verg. G. 2, 26 et saep.—Of the back of a chair, Tac. A. 15, 57.—
B. The mathematical arc, Sen. Q. N. 1, 10; Col. 5, 2, 9.—Hence, of the five parallel circles of the globe which bound the zones (or perhaps rather, the zones themselves): “via quinque per arcus,” Ov. M. 2, 129.
