Udal \U"dal\, n. & a. Udalborn \U"dal*born`\, Udaler \U"dal*er\,
   Udalman \U"dal*man\, etc.
      Vars. of {Odal}, etc. Obs. exc. in Shetland and the Orkney
      Islands, where udal designates land held in fee simple
      without any charter and free of any feudal character.

English Dictionary: Uthlande	by the DICT Development Group
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Udaler \U"dal*er\, Udalman \U"dal*man\, n.       In the Shetland and Orkney Islands, one who holds property by       udal, or allodial, right. --Sir W. Scott.