A PPO, or Preferred Provider Organization, is a system of managed health care where an insurance provider contracts with health care providers (hospitals or doctors) to provide lots of patients (and prompt payment) in exchange for lower rates from the health care providers.

Patients are encouraged to visit these providers by receiving discounts on services when they visit a doctor who is a member of the PPO. Basically, it's a "you scratch my back and I'll scratch yours" situation.