rattus

• ratus

Borrowed from a Germanic language, ultimately from Proto-Germanic *rattaz (“rat”).

rattus m (variously declined, genitive rattī or rattūs); second declension, fourth declension

1. (Medieval Latin) rat

In Classical Latin, the word mūs was applied to both mice and rats without distinction.

Second-declension noun or fourth-declension noun.

• Catalan: rata
• Italian: ratto
• Old French: rat, rate
  • Middle French: rat
    • French: rat
• Portuguese: rato
• Spanish: rata, rato, ⇒ ratón
• Translingual: Rattus, Rattus rattus

• rattus 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)
  ratus 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)
  [note: du Cange has only second declension forms and no fourth declension form]