Medicare glossary

The words Medicare uses, in the words you'd use.

Medicare has its own vocabulary, and plan documents assume you already know it. Each term below links to the guide that explains it in full.

Advance Beneficiary Notice (ABN): A notice a provider gives someone with Original Medicare before a service Medicare may not pay for. If you sign it and Medicare denies the claim, you may have to pay. Read the guide
Annual Notice of Change (ANOC): A notice Medicare Advantage and Part D plans send members each fall describing changes to costs, coverage and networks for the next year. Read the guide
Annual Wellness Visit: A yearly visit under Part B to create or update a personalized prevention plan. It is not a head-to-toe physical exam. Read the guide
Assignment: An agreement by a doctor or supplier to accept the Medicare-approved amount as full payment for covered services. Providers who don't accept assignment can charge more. Read the guide
Benefit period: The way Original Medicare measures your use of hospital and skilled nursing facility services under Part A. It starts when you're admitted as an inpatient and ends after 60 days in a row without inpatient or skilled nursing care. Read the guide
Coinsurance: Your share of the cost of a service, usually a percentage (for example, 20% of the Medicare-approved amount under Part B). Read the guide
Coordination of benefits: The rules that decide which coverage pays first (primary) and which pays second (secondary) when you have Medicare and another kind of coverage. Read the guide
Copayment: A fixed amount you pay for a covered service, such as a doctor visit or a prescription. Read the guide
Creditable prescription drug coverage: Drug coverage (for example, from an employer or union) expected to pay, on average, at least as much as standard Medicare drug coverage. Having it lets you delay Part D without a penalty. Read the guide
Custodial care: Help with daily activities such as bathing, dressing and eating. Medicare generally does not pay for custodial care when it's the only care you need. Read the guide
Deductible: The amount you pay for covered care before Medicare or your plan starts to pay. Read the guide
Dual eligible: Someone who qualifies for both Medicare and Medicaid, either fully or through a Medicare Savings Program. Read the guide
Durable medical equipment (DME): Equipment such as walkers, wheelchairs and hospital beds that a doctor orders for use at home. Part B covers medically necessary DME. Read the guide
End-Stage Renal Disease (ESRD): Permanent kidney failure that requires regular dialysis or a kidney transplant. People with ESRD can qualify for Medicare at any age. Read the guide
Evidence of Coverage (EOC): The document that explains in detail what a Medicare Advantage or Part D plan covers, what it costs and how its rules work. Read the guide
Excess charge: The amount, above the Medicare-approved amount, that a doctor who doesn't accept assignment may charge under Original Medicare. It is capped by law. Read the guide
Extra Help: A Medicare program that helps people with limited income and resources pay Part D premiums, deductibles and copayments. Also called the Low-Income Subsidy (LIS). Read the guide
Formulary: A plan's list of covered prescription drugs, usually grouped into cost tiers. Read the guide
General Enrollment Period: January 1 to March 31 each year, when people who missed their Initial Enrollment Period can sign up for Part B (and premium Part A). Read the guide
Guaranteed issue rights: Situations in which an insurance company must sell you certain Medigap policies, can't charge more for past or present health problems, and must cover pre-existing conditions. Read the guide
HMO (Health Maintenance Organization): A type of Medicare Advantage plan that generally requires you to use doctors and hospitals in its network, except in emergencies. Read the guide
Hold harmless: A rule that stops most people's Part B premium increase from being larger than their Social Security cost-of-living increase, so their net benefit doesn't fall. Read the guide
Hospice: Care for people who are terminally ill, focused on comfort rather than cure. Covered under Part A. Read the guide
Income-Related Monthly Adjustment Amount (IRMAA): An extra amount people with higher incomes pay on top of their Part B and Part D premiums, based on income from their tax return two years earlier. Read the guide
Initial Enrollment Period: The 7-month window around the month you turn 65 when you can first sign up for Medicare. Read the guide
Late enrollment penalty: An amount added to your Part B or Part D premium (and in some cases premium Part A) if you don't sign up when you're first eligible and don't have qualifying other coverage. Read the guide
Lifetime reserve days: Sixty extra days Part A will help pay for when you're in a hospital for more than 90 days in a benefit period. Once used, they don't renew. Read the guide
Maximum out-of-pocket limit (MOOP): The most you'll pay for covered Part A and Part B services in a year in a Medicare Advantage plan. Original Medicare has no such limit. Read the guide
Medical underwriting: The process an insurer uses to review your health history to decide whether to accept an application and what to charge. Read the guide
Medicare Advantage (Part C): A plan from a private company that contracts with Medicare to provide your Part A and Part B coverage, and usually Part D, instead of Original Medicare. Read the guide
Medicare Advantage Open Enrollment Period: January 1 to March 31, when people already in a Medicare Advantage plan can make one switch to another Medicare Advantage plan or back to Original Medicare. Read the guide
Medicare Beneficiary Identifier (MBI): The number on your Medicare card. It is not your Social Security number, and you should share it only with people you trust, such as your doctors and your plan. Read the guide
Medicare Open Enrollment: October 15 to December 7 each year, when you can join, switch or drop a Medicare Advantage or Part D plan, with changes starting January 1. Read the guide
Medicare Prescription Payment Plan: A way to pay your Part D out-of-pocket drug costs in monthly amounts across the year instead of all at the pharmacy. It doesn't lower what you owe. Read the guide
Medicare Savings Programs: State-run programs that help people with limited income and resources pay Medicare premiums and, in some cases, deductibles and coinsurance. Read the guide
Medicare Summary Notice (MSN): A statement people with Original Medicare get, showing the services billed to Medicare and what they may owe. It is not a bill. Read the guide
Medigap (Medicare Supplement Insurance): Insurance sold by private companies that helps pay costs Original Medicare doesn't, such as deductibles and coinsurance. It doesn't work with Medicare Advantage. Read the guide
Medigap Open Enrollment Period: The 6 months starting the first month you have Part B and are 65 or older. During it, insurers can't use medical underwriting to deny or price a Medigap policy. Read the guide
Network: The doctors, hospitals and pharmacies a plan contracts with to provide care to its members. Read the guide
Observation status: Outpatient hospital status used while doctors decide whether to admit you. Services are billed under Part B and the days don't count toward the 3-day inpatient stay needed for skilled nursing facility coverage. Read the guide
Original Medicare: Part A (hospital insurance) and Part B (medical insurance), run directly by the federal government. You can use any doctor or hospital in the US that accepts Medicare. Read the guide
Part A (Hospital Insurance): Covers inpatient hospital stays, care in a skilled nursing facility, hospice and some home health care. Read the guide
Part B (Medical Insurance): Covers doctors' services, outpatient care, medical supplies, durable medical equipment and preventive services. Read the guide
Part D (Drug Coverage): Prescription drug coverage offered by private plans, either as a standalone plan or included in a Medicare Advantage plan. Read the guide
PFFS (Private Fee-for-Service): A type of Medicare Advantage plan that sets how much it pays providers and how much you pay. Not every provider accepts it. Read the guide
PPO (Preferred Provider Organization): A type of Medicare Advantage plan with a network, where you can generally see out-of-network providers for a higher cost. Read the guide
Premium: The periodic payment to Medicare, an insurance company or a plan for coverage. Read the guide
Primary payer: The insurance that pays first on a claim. The secondary payer may then cover some of what's left. Read the guide
Prior authorization: Approval you or your provider must get from a plan before it will cover a service, supply or drug. Read the guide
Qualified Medicare Beneficiary (QMB) program: A Medicare Savings Program that pays Part A and Part B premiums, deductibles, coinsurance and copayments. Providers may not bill QMB enrollees for Medicare cost sharing. Read the guide
Senior Medicare Patrol (SMP): A national program that helps people with Medicare prevent, detect and report health care fraud, errors and abuse. Read the guide
Skilled nursing facility (SNF): A facility with the staff and equipment to give skilled nursing or rehabilitation care. Part A covers limited SNF care after a qualifying inpatient hospital stay. Read the guide
Special Enrollment Period (SEP): A window outside the usual enrollment periods when certain life events, such as losing job-based coverage or moving, let you sign up for or change Medicare coverage. Read the guide
Special Needs Plan (SNP): A Medicare Advantage plan limited to people with specific needs: those with both Medicare and Medicaid (D-SNP), certain chronic conditions (C-SNP), or who live in an institution (I-SNP). Read the guide
SSA-44: The Social Security form used to ask for a lower IRMAA because a life-changing event, such as retirement, reduced your income. Read the guide
Star ratings: Medicare's 1-to-5-star quality and performance ratings for Medicare Advantage and Part D plans, updated each year. Read the guide
State Health Insurance Assistance Program (SHIP): A state program that gives free, unbiased, one-on-one Medicare counseling. SHIP counselors don't sell insurance. Read the guide
Step therapy: A plan rule that you try a lower-cost drug that treats your condition before the plan will cover a higher-cost drug. Read the guide
Third-party marketing organization (TPMO): A business, such as an agency, broker or lead generator, that sells or markets Medicare Advantage or Part D plans on behalf of plans. TPMOs must tell you they don't offer every plan in your area. Read the guide
Tier: A cost level on a drug plan's formulary. Drugs on lower tiers generally cost you less than drugs on higher tiers. Read the guide
Trial right: A guaranteed issue right that lets someone who tries Medicare Advantage for the first time return to Original Medicare and buy certain Medigap policies within the first 12 months. Read the guide
Welcome to Medicare preventive visit: A one-time visit available within the first 12 months you have Part B, reviewing your health and the preventive services you need. Read the guide

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General information about the federal Medicare program, not advice about your situation. Figures are for 2026 unless stated and change every year; last reviewed September 29, 2026. Quote My Policy is a private company. Not connected with or endorsed by the United States government or the federal Medicare program.

Quote My Policy does not sell Medicare plans on this site. For plan-specific help, contact Medicare at 1-800-MEDICARE (1-800-633-4227) (TTY 1-877-486-2048, 24 hours a day, 7 days a week) or your State Health Insurance Assistance Program.