出典:Wiktionary
出典:『Wiktionary』 (2025/11/25 20:46 UTC 版)
The NIL suggests that the term was directly inherited from Proto-Indo-European *h₂eḱus (“pointed”), from the root *h₂eḱ- (“sharp”). However, De Vaan argues that the noun acus was a later formation from the same root. Though, De Vaan does suggest that this same Proto-Indo-European u-stem is the source of acūpedius and acuō (“sharpen, whet”).
acus f (genitive acūs); fourth declension
Fourth-declension noun.
| singular | plural | |
|---|---|---|
| nominative | acus | acūs |
| genitive | acūs | acuum |
| dative | acuī | acibus |
| accusative | acum | acūs |
| ablative | acū | acibus |
| vocative | acus | acūs |
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”).
acus n (genitive aceris); third declension
Third-declension noun (neuter, imparisyllabic non-i-stem).
| singular | plural | |
|---|---|---|
| nominative | acus | acera |
| genitive | aceris | acerum |
| dative | acerī | aceribus |
| accusative | acus | acera |
| ablative | acere | aceribus |
| vocative | acus | acera |
出典:Wikipedia