beaver: [OE] Like bear, beaver appears to mean etymologically ‘brown animal’. Old English beofor or befor came from a prehistoric West and North Germanic *bebruz, which in turn went back to an Indo-European *bhebhrús, a derivative of the base *bhru- ‘brown’. Other words for ‘beaver’ from the same source include Czech bobr, Lithuanian bebrùs, and Latin fiber. [beaver etymology, beaver origin, 英语词源]