bièvre

from Gaulish bebros (see befer in Welsh, Old Breton bever, regional Breton bieuzr, Scottish beabhar), from the Proto-Indo-European bhebhrus, attested as beber in Late Latin (cf. Latin fiber, English beaver, German biber, Czech bobr, Avestan bawra, bawri, Sanskrit babhrús, "mongoose"), from bhrus, "brown".