What is the meaning of referral?

noun

• A person whose case has been referred to a specialist or professional group.
  • usage: "the patient is a referral from Dr. Bones"
• A recommendation to consult the (professional) person or group to whom one has been referred.
  • usage: "the insurance company says that you need a written referral from your physician before seeing a specialist"
• The act of referring (as forwarding an applicant for employment or referring a matter to an appropriate agency. ).