Source : Webster's Revised Unabridged Dictionary (1913)

Privy \Priv"y\, n.; pl. {Privies}.
   1. (Law) A partaker; a person having an interest in any
      action or thing; one who has an interest in an estate
      created by another; a person having an interest derived
      from a contract or conveyance to which he is not himself a
      party. The term, in its proper sense, is distinguished
      from party. --Burrill. Wharton.

   2. A necessary house or place; a backhouse.