Source : Webster's Revised Unabridged Dictionary (1913)

Domesday \Domes"day`\, n.
   A day of judgment. See {Doomsday}. [Obs.]

   {Domesday Book}, the ancient record of the survey of most of
      the lands of England, made by order of William the
      Conqueror, about 1086. It consists of two volumes, a large
      folio and a quarto, and gives the proprietors' tenures,
      arable land, woodland, etc. [Written also {Doomsday
      Book}.]

Source : WordNet®

Domesday Book
     n : record of a British land survey ordered by William the
         Conqueror