Definition from Wiktionary, the free dictionary
Jump to navigation Jump to search



Etymology 1[edit]

From Proto-Italic *akus, from Proto-Indo-European *h₂eḱus, from the root *h₂eḱ- (sharp). Related to acuō (sharpen, whet) and aciēs (edge).[1]


acus f (genitive acūs); fourth declension

  1. a needle, a pin
  2. bodkin

Fourth-declension noun.

Case Singular Plural
Nominative acus acūs
Genitive acūs acuum
Dative acuī acibus
Accusative acum acūs
Ablative acū acibus
Vocative acus acūs
Derived terms[edit]
  • Aromanian: ac
  • Dalmatian: juac
  • Istriot: ago
  • Italian: ago
  • Neapolitan: aco
  • Northern-Italo Romance:
    • Romagnol: êg m
  • Romanian: ac
  • Sardinian: àcu

Etymology 2[edit]

From Proto-Italic *akos, from Proto-Indo-European *h₂éḱos (tip, bristle; ear/blade of grain, awn, chaff), from the root *h₂eḱ- (sharp). Cognates include agna (ear) and Proto-Germanic *ahaz (ear), Proto-Germanic *aganō, *ahanō (chaff) (> English awn), Ancient Greek ἄχυρον (ákhuron) (> Greek άχυρο (áchyro, hay)), and Tocharian B āke (tip, peak, end).[1]


acus n (genitive aceris); third declension

  1. bran, awn, chaff
    Synonym: āplūda

Third-declension noun (neuter, imparisyllabic non-i-stem).

Case Singular Plural
Nominative acus acera
Genitive aceris acerum
Dative acerī aceribus
Accusative acus acera
Ablative acere aceribus
Vocative acus acera
Derived terms[edit]


  1. 1.0 1.1 Wodtko, Dagmar S.; Irslinger, Britta; Schneider, Carolin (2008), “*h₂ek̂-”, in Nomina im indogermanischen Lexikon [Nouns in the Indo-European Lexicon] (in German), Heidelberg: Universitätsverlag Winter, page 287–300
  • Ernout, Alfred; Meillet, Antoine (1985), “acus”, in Dictionnaire étymologique de la langue latine: histoire des mots (in French), with additions and corrections of Jacques André, 4th edition, Paris: Klincksieck, published 2001, page 7
  • acus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
  • acus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
  • acus in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
  • acus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette
  • Carl Meißner; Henry William Auden (1894) Latin Phrase-Book[1], London: Macmillan and Co.
    • you have hit the nail on the head: rem acu tetigisti
  • acus”, in Harry Thurston Peck, editor (1898) Harper's Dictionary of Classical Antiquities, New York: Harper & Brothers
  • acus”, in William Smith et al., editor (1890) A Dictionary of Greek and Roman Antiquities, London: William Wayte. G. E. Marindin