Consubstantiation

n.
  1. An identity or union of substance.
  2. (Theol.) The actual, substantial presence of the body of Christ with the bread and wine of the sacrament of the Lord's Supper; impanation; -- opposed to transubstantiation.

This view, held by Luther himself, was called consubstantiation by non Lutheran writers in contradistinction to transsubstantiation, the Catholic view.