The Collaborative International Dictionary of English v.0.48:

Proprietary \Pro*pri"e*ta*ry\, a. [L. proprietarius.]
   Belonging, or pertaining, to a proprietor; considered as
   property; owned; as, proprietary medicine.
   [1913 Webster]

   Proprietary articles, manufactured articles which some
      person or persons have exclusive right to make and sell.
      --U. S. Statutes.
      [1913 Webster]