acus

Latin

Pronunciation

• (Classical) IPA^(key): /ˈa.kus/, [ˈa.kʊs]
• (Ecclesiastical) IPA^(key): /ˈa.kus/, [ˈaː.kus]

Etymology 1

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

Noun

acus f (genitive acūs); fourth declension

2. a needle, a pin
3. bodkin

Declension

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

• acū pingō (“I embroider”)
• foramen acūs (“the eye of a needle”)
• rem acū tetigistī, acū tetigistī
• acia
• acuārius
• acucula
• acula
• aculeus
• acuō
• aquifolium

 

Descendants

• Aromanian: ac
• Dalmatian: juac
• English: acupuncture
• Istriot: ago
• Italian: ago

• Neapolitan: aco
• Romanian: ac
• Sardinian: àcu
• Vulgar Latin: *acūcla (see there for further descendants)

Etymology 2

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”).

Noun

acus n (genitive aceris); third declension

2. bran, awn, chaff

   Synonym: āplūda

Declension

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

• acerātus
• acerōsus

References

• Ernout, Alfred; Meillet, Antoine (2001), “acus”, in Dictionnaire étymologique de la langue latine: histoire des mots (in French), with additions and corrections of André J., 4th edition, Paris: Klincksieck, 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, 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