Excalibur, in Arthurian legend, King Arthur’s sword. As a boy, Arthur alone was able to draw the sword out of a stone in which it had been magically fixed. This account is contained in Sir Thomas Malory’s 15th-century prose rendering of the Arthurian legend, but another story in the same work suggests that it was given to Arthur by the Lady of the Lake and that, when the king lay mortally wounded after his last battle, he ordered the faithful Sir Bedivere to go to the water and throw the sword into it. An arm rose to catch it, brandished Excalibur three times, and then disappeared.
There was a famous sword in Irish legend called Caladbolg, from which Excalibur is evidently derived by way of Geoffrey of Monmouth, whose Historia regum Britanniae refers to Arthur’s sword as Caliburn. Malory says that Excalibur means “cut-steel.”