castor

beaver (aquatic mammal); castor (hat made from beaver fur)

“Un amas de guenilles lui recouvrait les épaules, et un vieux castor défoncé, s'arrondissant en cuvette, lui cachait la figure; […].”

Inherited from Middle French castor, from Old French castor, borrowed from Latin castor, itself from Ancient Greek κάστωρ (kástōr). Though borrowed into French early on, the word remained a more learned term at first, while bièvre was the popular synonym.