The purpose of this Nomenclatural Note is to demonstrate that 1) the objective junior synonym Trogontherium cuvieri Fischer, 1814 should have precedence over Castor trogontherium Cuvier, 1809, and 2) the binomen should be attributed to Fischer (1814) instead of the widely cited Fischer (1809). When, in 1809, Johann Gotthelf Fischer described the fossil skull of a beaver found near the Sea of Azov (Russia), he erected for it the genus name Trogontherium without proposing a species name. The skull later became the holotype of what is now commonly cited as Trogontherium cuvieri Fischer, 1809, even though this binomen had not been formally proposed that year. Later that year, Georges Cuvier used the name Castor trogontherium to refer to the same specimen. We found an apparently previously-overlooked 1814 publication by Fischer in which the binomen Trogontherium cuvieri was used for the first time. Although an objective junior synonym of Castor trogontherium Cuvier, 1809, that senior synonym has not been used as a valid name since 1884 and, in compliance with the Code, we suggest reversing precedence and conclude that the correct name for the European giant beaver is Trogontherium cuvieri Fischer, 1814.