Medicare Glossary

A helpful guide to understanding common terms and acronyms you'll encounter when learning about Medicare.

Appeal

An action you can take if you disagree with a coverage or payment decision made by Medicare or your Medicare plan.

Coinsurance

An amount you may be required to pay as your share of the cost for services after you pay any deductibles. Coinsurance is usually a percentage (for example, 20%).

Copayment

An amount you may be required to pay as your share of the cost for a medical service or supply, like a doctor's visit. A copayment is usually a set amount, rather than a percentage.

Deductible

The amount you must pay for health care or prescriptions before Original Medicare, your prescription drug plan, or your other insurance begins to pay.

Formulary

A list of prescription drugs covered by a prescription drug plan or another insurance plan.

Medically Necessary

Health care services or supplies needed to diagnose or treat an illness, injury, condition, disease, or its symptoms and that meet accepted standards of medicine.

Network

The facilities, providers, and suppliers your health insurer or plan has contracted with to provide health care services.

Premium

The periodic payment to Medicare, an insurance company, or a health care plan for health or prescription drug coverage.