The Collaborative International Dictionary of English v.0.48:

Impanation \Im"pa*na"tion\, n. [Cf. F. impanation. See
   Impanate, a.] (Eccl.)
   Embodiment in bread; the supposed real presence and union of
   Christ's material body and blood with the substance of the
   elements of the eucharist without a change in their nature;
   -- distinguished from transubstantiation, which supposes a
   miraculous change of the substance of the elements. It is
   akin to consubstantiation.
   [1913 Webster]