The Collaborative International Dictionary of English v.0.48:

Domesday \Domes"day`\, n.
   A day of judgment. See Doomsday. [Obs.]
   [1913 Webster]

   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.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Doomsday \Dooms"day`\, n. [AS. d?mes d[=a]g. See Doom, and
   Day.]
   1. A day of sentence or condemnation; day of death. "My
      body's doomsday." --Shak.
      [1913 Webster]

   2. The day of the final judgment.
      [1913 Webster]

            I could not tell till doomsday.       --Chaucer.
      [1913 Webster]

   Doomsday Book. See Domesday Book.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Doomsday Book
    n 1: record of a British census and land survey in 1085-1086
         ordered by William the Conqueror [syn: Domesday Book,
         Doomsday Book]