From Proto-Balto-Slavic *bébrus, from Proto-Indo-European *bʰébʰrus, reduplicated form of *bʰrew- (“shiny, light brown”) (whence also bērs). The original meaning of bebrs was thus “brown one.” Cognates include Lithuanian bẽbras, bebrùs, Old Prussian bebrus, Proto-Slavic *bebrъ, *bobrъ, *bьbrъ (Old East Slavic бебръ (bebrŭ), бобръ (bobrŭ), Russian бобр (bobr), Belarusian бабёр (babjór), бабра́к (babrák), Ukrainian бобе́р (bobér), бібр (bibr), Bulgarian бъ́бър (bǎ́bǎr), бо́бър (bóbǎr), бе́бер (béber), Czech bobr, Polish bóbr), Old High German bibar, German Biber, English beaver, Avestan 𐬠𐬀𐬎𐬎𐬭𐬀 (bauura), Latin fiber.