Definition of "Nibelung"

[…] and at the same Time flattered himself, that the Lombards and People of Acquitaine, whom he had lately conquered, having Kings of their own, would not be so easily tempted to shake off the Yoke, as if their Countries were made Provinces of France. [footnote] Eginhard. in vit. Carol. Chron. Nibelung. in appendice. Annal. Moiffiac.

1759, Archibald Bower, The History of the Popes: From the Foundation of the See of Rome to the Present Time‎, volume 4, London: Author, Hadrian, Ninety—Fourth Bishop of Rome, page 62

The Song of the Nibelungen, and the Lament.

1814, Robert Jamieson, Walter Scott, Henry William Weber, Illustrations of northern antiquities, from the earlier Tentonie and Scandinavian romances: being an abstract of the Book of heroes, and Nibelungen lay; with translation of metrical tales, from the Old German, Danish, Swedish, and Icelandie languages; with notes and dissertations.‎, Edinburgh: Printed by J. Ballantyne and co., for Longman, Hurst, Rees, Orme, and Brown, Of the Teutonic Cyclus of Romance, page 25