Source : Webster's Revised Unabridged Dictionary (1913)

Earldom \Earl"dom\, n. [AS. eorl-d?m; eorl man, noble + -d?m
   -dom.]
   1. The jurisdiction of an earl; the territorial possessions
      of an earl.

   2. The status, title, or dignity of an earl.

            He [Pulteney] shrunk into insignificancy and an
            earldom.                              --Chesterfield.

Source : WordNet®

earldom
     n 1: the dignity or rank or position of an earl or countess
     2: the domain controlled by an earl or count or countess