Source : Webster's Revised Unabridged Dictionary (1913)

Nibelungs \Ni"be*lungs\, n. pl.; sing. {Nibelung}.
   In German mythology, the children of the mist, a race of
   dwarfs or demonic beings, the original possessors of the
   famous hoard and ring won by Siegfrid; also, the Burgundian
   kings in the Nibelungenlied.