Excalibur

from WordNet (r) 3.0 (2006)

Excalibur
    n 1: the legendary sword of King Arthur

from The Collaborative International Dictionary of English v.0.48

Excalibur \Ex*cal"i*bur\, n.
   The name of King Arthur's mythical sword. [Written also
   {Excalibar}, {Excalibor}, {Escalibar}, and {Caliburn}.]
   --Tennyson. Excamb