Source : Webster's Revised Unabridged Dictionary (1913)

Impropriation \Im*pro`pri*a"tion\, n.
   1. The act of impropriating; as, the impropriation of
      property or tithes; also, that which is impropriated.

   2. (Eng. Eccl. Law)
      (a) The act of putting an ecclesiastical benefice in the
          hands of a layman, or lay corporation.
      (b) A benefice in the hands of a layman, or of a lay
          corporation.