The Collaborative International Dictionary of English v.0.48:

Hereditable \He*red"i*ta*ble\, a. [LL. hereditabilis, fr.
   hereditare to inherit, fr. L. hereditas heirship inheritance,
   heres heir: cf. OF. hereditable. See Heir, and cf.
   Heritable.]
   1. Capable of being inherited. See Inheritable. --Locke.
      [1913 Webster]

   2. Qualified to inherit; capable of inheriting.
      [1913 Webster]