LATIN DICTIONARYLexicon Latīnum
noun · masculinefourth declension

arcus

arcus m (genitive arcūs)
Classical[ˈar.kʊs]Ecclesiastical[ˈar.kus]
Mille Verba core vocabulary

Meaning

  1. masculinearc, arch
  2. masculinebow (arc-shaped weapon used for archery)
  3. masculinerainbow

Latīnē defined in Latin in our graded readers

quō sagittae mittuntur; in orbem flexus est.
arcus -ūs m — in Mille Verba, Bellum et Arma
aedificium curvum
arcus -ūs (m) — in Epistulae, ch. 20

Declension

declension
formsingularplural
nominativearcusarcūs
arcora
genitivearcūsarcuum
dativearcuīarcubus
accusativearcumarcūs
arcora
ablativearcūarcubus
vocativearcusarcūs

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.—
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.

Origins

From Proto-Italic *arkuos (“bow”), from Proto-Indo-European *h₂erkʷos (“bow, arrow”). Cognate to Old English earh, whence English arrow, as well as Proto-Slavic *orkyta (“willow”) and Ancient Greek ἄρκευθος (árkeuthos, “juniper”), owing to juniper and willow twigs being used to make bows due to their flexibility.

Gallo-Romance
  • Catalanarc
  • Occitanarc
  • Frencharcfrom unknown arc
  • Englisharcfrom unknown arc
  • Frencharchefrom unknown arche
  • Englisharchfrom unknown arche
  • Normanarchefrom unknown arche
Insular Romance
  • Sardinianalcu
  • Sardinianarcu
Italo-Dalmatian
  • Italianarco
  • Englisharcofrom Italian arco
  • Istriotarco
  • Maltesearkufrom Sicilian arcu
Ibero-Romance
  • Portuguesearcofrom Old Galician-Portuguese arco
  • Spanisharcofrom Old Spanish arco
  • Asturianarcu
  • Falaarcufrom Old Galician-Portuguese arco
  • Falaalcufrom Old Galician-Portuguese arco
  • Galicianarcofrom Old Galician-Portuguese arco
  • Indonesianarkufrom Old Galician-Portuguese arco
  • Cebuanoarkofrom Old Spanish arco
  • Chibchaarcofrom Old Spanish arco
  • Ilocanoarkofrom Old Spanish arco
Balkano-Romance
  • Romanianarc
  • Aromanianarcu
Borrowings
  • Englisharcus
  • Esperantoarko
  • Idoarko
  • Indonesianarkus
  • Icelandicarkfrom Middle Low German ark
  • Norwegian Bokmålarkfrom Middle Low German ark
  • Norwegian Nynorskarkfrom Middle Low German ark
  • Finnisharkkifrom Middle Low German ark
  • Latvianarkafrom Russian а́рка
  • Lithuanianarkafrom Russian а́рка
Rhaeto-Romance
  • Friulianarc
  • Romanshartg
  • Romansharch
Gallo-Italic
  • Emilianèrc
  • Ligurianerco
  • Piedmonteseerch
  • Piedmonteseerche

In the Academy Smith's classical dictionaries

AntiquitiesArcusArcus (βιός, τόξον), the bow used for shooting arrows, is one of the most ancient weapons, but its use in warfare was early abandoned by the Greeks in…

Quick answers

What does arcus mean in Latin?
arcus, a noun, means “arc, arch; bow (arc-shaped weapon used for archery); rainbow”.
What is the genitive of arcus?
The genitive singular is arcūs. arcus is masculine, fourth declension.
How do you pronounce arcus?
In classical Latin, [ˈar.kʊs]; in ecclesiastical (church) Latin, [ˈar.kus].