Source : Webster's Revised Unabridged Dictionary (1913)

Parol \Pa*rol"\, a.
   Given or done by word of mouth; oral; also, given by a
   writing not under seal; as, parol evidence.

   {Parol arrest} (Law), an arrest in pursuance of a verbal
      order from a magistrate.

   {Parol contract} (Law), any contract not of record or under
      seal, whether oral or written; a simple contract.
      --Chitty. Story.