Meaning of Lyonnesse

Ly•on•nesse

Pronunciation: (lī"u-nes'), [key]
— n. Arthurian Romance.
  1. the mythical region where Sir Tristram was born, located near Cornwall in SW England and supposed to have been submerged by the sea.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.