Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

arcus, ūs, m. (the orthography, arquus (cf. arquatus), is freq. in MSS., like quum for cum, quur for cur, etc.; cf. Freund ad Cic. Mil. p. 31 sq. Thus Charis. p. 92 P. upon Cic. N. D. 3, 20, 51, reads arcuis; Prisc. p. 712 P. arci; and Non. p. 425, 5, upon Lucr. 6, 526, arqui; but the distinction which the latter gram. points out (arcus suspensus fornix appellatur; arquus non nisi qui in caelo apparet, quam Irim poëtae dixerunt) does not seem to be well founded.
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,

  1. I. A bow (syn. cornu).
    1. 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.
    2. 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.
    3. 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.
  2. II. Transf.
    1. 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.
    2. 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.

arx, arcis, f. [arx ab arcendo, quod is locus munitissimus rubis, a quo facillime possit hostis prohiberi, Varr. L. L. 5, § 151 Müll; cf. Serv. ad Verg. A. 1, 20; Isid. Orig. 15, 2, 32; Doed. Syn. IV. p. 428; v. arceo], a stronghold, castle, citadel, fortress, ἀκρόπολις; in Rome, the Capitolium.

  1. I.
    1. A. Lit.: arce et urbe orba sum, Enn. ap. Cic. Tusc. 3, 19, 44 (Trag. v. 114 Müll.): optumates, Corinthum quae arcem altam habetis, id. ap. ejusd. Fam. 7, 6: edicite per urbem ut omnes qui arcem astuque accolunt, cives, etc.; Att. ap. Non. p. 357, 14: Illa autem in arcem [hinc] abiit, Plaut. Bacch. 4, 8, 59; so id. Ps. 4, 6, 2: In arcem transcurso opus est, Ter. Hec. 3, 4, 17: Condere coeperunt urbīs arcemque locare, Lucr. 5, 1107: arcis servator, candidus anser, id. 4, 683: munire arcem, Cic. Pis. 34 fin.: cum Tarento amisso arcem tamen Livius retinuisset, id. de Or. 2, 67, 273: arx intra moenia in immanem altitudinem edita; Liv. 45, 28: arx Sion, Vulg. 2 Reg. 5, 7: arx Jerusalem, ib. 1 Macc. 13, 49: Romana, Liv. 1, 12: Capitolina, id. 6, 20; cf. id. 3, 18: Sabinus arcem Capitolii insedit mixto milite, Tac. H. 3, 69; Suet. Claud. 44 et saep. As the place on which auguries were received (cf. auguraculum): ut cum in arce augurium augures acturi essent, Cic. Off. 3, 16, 66; so Liv. 1, 18 and 24.
      Hence,
    2. B. Trop., defence, prolection, refuge, bulwark, etc.: Castoris templum fuit te consule arx civium perditorum, receptaculum veterum Catilinae militum, castellum forensis latrocinii, Cic. Pis. 5, 11: haec urbs, lux orbis terrarum atque arx omnium gentium, id. Cat. 4, 6; cf. id. Agr. 1, 6, 18: Africa arx omnium provinciarum, id. Lig. 7, 22: Stoicorum, id. Div. 1, 6, 10: arx finitimorum, Campani, Liv. 7, 29; 37, 18: tribunicium auxilium et provocationem, duas arces libertatis tuendae, id. 3, 45: arx ad aliquid faciendum, id. 28, 3: eam urbem pro arce habiturus Philippus adversus Graeciae civitates, id. 33, 14; Flor. 3, 6, 5: quasi arx aeternae dominationis, Tac. A. 14, 31.
    3. C. As the abode of tyrants, a poet. designation of tyranny (cf. Ascon. ad Cic. Div. in Caecil. 5), Claud. IV. Cons. Hon. 293 Heins.: cupidi arcium, Sen. Thyest. 342; cf. id. Contr. 4, 27: non dum attigit arcem, Juris et humani culmen, Luc. 7, 593 Corte; cf. id. 8, 490, and 4, 800; Tert. Apol. 4.
    4. D. Prov.: arcem facere e cloacā, to make a mountain of a mole-hill, Cic. Planc. 40.
  2. II. Since castles were generally on a height, meton., a height, summit, pinnacle, top, peak (usu. poet. and in Aug. and postAug. prose), lit. and trop.
    1. A. Lit.: summā locum sibi legit in arce, upon the extreme height, Ov. M. 1, 27; cf. id. ib. 12, 43.
      So,
      1. 2. In partic.
        1. a. Of mountains: Parnasi constitit arce, Ov. M. 1, 467: arce loci summā, id. ib. 11, 393: Rhipaeae arces, Verg. G. 1, 240: flērunt Rhodopeïae arces, id. ib. 4, 461: septemque unā sibi muro circumdedit arces, id. ib. 2, 535: primus inexpertas adiit Tirynthius arces, i. e. Alpes, Sil. 3, 496; cf. Drak. ad id. 15, 305; Val. Fl. 3, 565: impositum arce sublimi oppidum cernimus, Petr. 116; cf. id. 123, 205, and 209.
        2. b. Of houses built on an eminence, Petr. 121, 107, and 293.
        3. c. Of the citadel of heaven: quae pater ut summā vidit Saturnius arce, Ov. M. 1, 163: summam petit arduus arcem, id. ib. 2, 306: sideream mundi qui temperat arcem, id. Am. 3, 10, 21.
        4. d. Of the heavens themselves: aetheriae arces, Ov. Tr. 5, 3, 19: arces igneae, Hor. C. 3, 3, 10: caeli quibus adnuis arcem, Verg. A. 1, 250; cf. id. ib. 1, 259.
        5. e. Of temples erected on an eminence: dexterā sacras jaculatus arces, Hor. C. 1, 2, 3.
        6. f. Of the head: arx corporis, Sen. Oedip. 185; Claud. IV. Cons. Hon. 235.
    2. B. Trop., height, head, summit, etc. (rare): celsā mentis ab arce, Stat. S. 2, 2, 131: summae laudum arces, Sil. 13, 771; Sid. Carm. 2, 173: ubi Hannibal sit, ibi caput atque arcem totius belli esse, head and front, Liv. 28, 42: arx eloquentiae, Tac. Or. 10.