Source : Webster's Revised Unabridged Dictionary (1913)

Ratable \Rat"a*ble\, a.
   1. Capable of being rated, or set at a certain value.

            Twenty or[ae] were ratable to [at] two marks of
            silver.                               --Camden.

   2. Liable to, or subjected by law to, taxation; as, ratable
      estate.

   3. Made at a proportionate rate; as, ratable payments. --
      {Rat"a*ble*ness}, n. -- {Rat"a*bly}, adv.

Source : WordNet®

ratable
     adj : liable to payment of rates or taxes; "the ratable value of
           property" [syn: {rateable}]