Source : Webster's Revised Unabridged Dictionary (1913)

Decumbiture \De*cum"bi*ture\ (?; 135), n.
   1. Confinement to a sick bed, or time of taking to one's bed
      from sickness. --Boyle.

   2. (Astrol.) Aspect of the heavens at the time of taking to
      one's sick bed, by which the prognostics of recovery or
      death were made.