Preferred Provider Organization. A health care organization composed of physicians, hospitals, or other providers which provides health care services at a reduced fee. A PPO is similar to an HMO, but care is Paid for as it is received instead of in Advance in the form of a scheduled fee. PPOs may also Offer more flexibility by allowing for visits to out-of-network professionals at a greater Expense to the Policy holder. Visits within the network require only the payment of a small fee. There is often a Deductible for out-of-network expenses and a higher co-payment. A Policy holder will have a primary physician within the network who will handle referrals to specialists that will be covered by the PPO. After any visit, the Policy holder must submit a Claim, and will be reimbursed for the visit minus his/her co-payment.