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