Medicare Glossary

Fact Checked
Reviewed by: Kelly Blackwell, Certified Senior Advisor®, Ron Elledge, Medicare consultant
Updated: January 15, 2022

Use this quick reference to help you understand commonly used Medicare terms.

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Kelly Blackwell
Certified Senior Advisor (CSA)®
Kelly Blackwell
Certified Senior Advisor (CSA)®

Kelly Blackwell is a Certified Senior Advisor (CSA)®. She has been a healthcare professional for over 30 years, with experience working as a bedside nurse and as a Clinical Manager. She has a passion for educating, assisting and advising seniors throughout the healthcare process.

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Ron Elledge
Medicare Consultant
Ron Elledge
Medicare Consultant

Ron Elledge is a seasoned Medicare consultant and author of “Medicare Made Easy.” As a Medicare expert, he regularly consults beneficiaries on Medicare rules, regulations, and strategies.


Annual Enrollment Period

If you are already enrolled in  Medicare Part A and B, you can enroll in a Medicare Advantage or Prescription Drug Plan (PDP) during the Annual Enrollment Period (AEP). If you are currently on a Medicare Advantage or PDP plan, you can make changes to your plan during this time. This enrollment period occurs annually from October 15th through December 7th, with coverage beginning on January 1st.

Annual Notice of Changes (ANOC)

A document provided by each Medicare plan to all enrollees detailing any changes in coverage, costs, or service area that will go into effect in January of the approaching year. Medicare requires that health plans notify you of these changes by mail by  September you can review them prior to the Annual Enrollment Period.


An agreement by your doctor, provider, or supplier to be paid directly by Medicare, to accept the payment amount Medicare approves for the service, and not to bill you for any more than the Medicare deductible and coinsurance. If you see a provider who accepts assignments, you will not incur excess charges.


An individual who has health insurance coverage through the Medicare or Medicaid program.

Benefit Period

A benefit period is the space of time that begins on the day that you are admitted to either a hospital or skilled nursing facility. The period ends sixty consecutive days after you last receive care at either a hospital or skilled nursing facility. Each benefit period has its own inpatient hospital deductible cost that you must pay. A new benefit period begins if youare admitted to a hospital or skilled nursing facility after a benefit period is closes. There is no limit to the number of benefit periods provided.


The percentage of the cost of health care services or prescription drugs that you must pay after you have met your plan’s deductible.


A flat rate, out-of-pocket payment that you must  pay for prescription drugs or health care services. Copayments are preset and may vary based upon the type of service you receive . Copayments and coinsurance for in-network Medicare-covered services go toward your maximum out-of-pocket costs.

Creditable prescription drug coverage

Prescription drug coverage (for example, from an employer or union) that’s expected to pay, on average, at least as much as Medicare’s standard prescription drug coverage. If you have this kind of coverage when you become eligible for Medicare, you can generally keep that coverage without paying a penalty, if you decide to enroll in Medicare prescription drug coverage later.


The amount that you have to pay for medical services or prescription drugs before your health care plan, prescription drug plan, or Medicare begins to pay.

Durable Medical Equipment (DME)

Medical equipment ordered for your use in the home by a physician to treat a medical condition or illness. Durable Medical Equipment is covered as part of home health services under Medicare Part B. Wheelchairs, hospital beds, and walkers are all examples of DME.


End-Stage Renal Disease (ESRD)

Permanent kidney failure that requires a regular course of dialysis or a kidney transplant. Learn more about eligibility requirements for Medicare if you have ESRD.

Emergency Services

An “emergency medical condition” is defined by Medicare as a “medical condition manifesting itself by acute symptoms of severity (including severe pain) that a prudent layperson who possesses an average knowledge of health and medicine, could reasonably expect the absence of immediate medical attention to result in: (a) placing the health of the individual in serious jeopardy; (b) serious impairment of bodily functions; or (c) serious dysfunction of any bodily organ or part of the body. Medicare covers emergency services.

Evidence of Coverage (EOC)

The document health plans provide each year to both new enrollees and renewing enrollees of Medicare Advantage and Medicare Part D Plans. The EOC provides details of the plan’s benefits and costs and acts as proof that you are enrolled. Review the EOC each year to make sure your plan still meets your needs.


Items and services that are not covered by your health care plan.

Extra Help

A Medicare program to help people with limited income and resources pay Medicare prescription drug program costs, like premiums, deductibles, and coinsurance. Learn more Extra Help here.


A published list of prescription drugs that a health insurance plan will cover. Prescription drug plans and Medicare Advantage publish a new list each year, and are required to post it  on their websites no later than October 15th. You can get a printed copy upon request. The formulary is also referred to as the Prescription Drug Guide.

Group health plan

In general, a health plan offered by an employer or employee organization that provides health coverage to employees and their families. If you have group health plan coverage when you are eligible for Medicare, you may defer enrollment in Plan B.

Guaranteed issue rights (also called “Medigap protections”)

Rights you have in certain situations when insurance companies are required by law to sell or offer you a Medigap policy. In these situations, an insurance company can’t deny you a Medigap policy, or place conditions on a Medigap policy, like exclusions for pre-existing conditions, and can’t charge you more for a Medigap policy because of a past or present health problem.

Health Maintenance Organization (HMO)

A type of health insurance coverage in which you selects and receive care from a primary care physician (PCP) from within the plan’s network. When specialized care is required, you must get a referral from your PCP to a specialist within the HMO’s network.Hospital care is also limited to facilities included in the plan’s network, although exceptions are made for emergencies.


Initial Coverage Election Period (ICEP)

For most people, this period occurs at the same time as their Initial Enrollment Period (IEP) for Original Medicare Parts A and B. For example, if you turn 65 on June 14th, your IEP for Parts A and B will run from March 1st through September 30th, and your ICEP for Medicare Advantage will run the same months as your IEP.

If you delay enrollment in Part B and enroll outside of your Initial Enrollment Period, then your ICEP for Medicare Advantage begins the three-month period before your Part B start date and ends the last day of the month before your Part B coverage starts. For example, if your Part B coverage start date is June 1st, your ICEP for Medicare Advantage runs from March 1st through May 31st with coverage beginning on June 1st. You do not have an additional three months after your Part B start date to enroll in a Medicare Advantage plan. If you do not apply for coverage beginning at the same time as your Part B start date, then you will have to wait until the next annual enrollment period. (See Annual Enrollment Period)

In-Network Provider

Also known as a participating provider, an in-network provider can be a hospital or medical facility, a physician or a pharmacy with whom a  health care plan has contracted for services at an agreed upon rate.

Limiting Charge

An established endpoint beyond which physicians or other health care suppliers that don’t accept assignment are permitted to charge for a covered service. The limiting charge is 15% above the amount that Medicare has approved for a specific service, and it is your responsibility to pay unless you have purchased a Medigap policy that pays the excess charge. Only some services have a limiting charge. Equipment and supplies do not have one. The limiting charge does not apply to in-network Medicare Advantage Plan coverage.

Long-term care

Services that include medical and non-medical care provided to people who are unable to perform basic activities of daily living, like dressing or bathing. Long-term supports and services can be provided at home, in the community, in assisted living, or in nursing homes. Individuals may need long-term supports and services at any age. Medicare and most health insurance plans don’t pay for long-term care.



A program that is jointly operated through the federal and state governments to cover health care costs for people who are either low income or who have limited resources. Individuals who qualify for both Medicaid and Medicare generally have most of their medical costs covered.

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.

Medicare Advantage (see Medicare Part C)

A type of Medicare benefits plan that is offered through private insurance companies rather than the federal government. Medicare Advantage (MA) Plans can be offered in a variety of formats, including Health Maintenance Organizations (HMOs), Preferred Provider Organizations (PPOs), Medical Savings Accounts (MSAs), Special Needs Plans (SNPs), and Private Fee-for-Service (PFFS) plans.

Medicare Advantage plans are contracted and approved by Medicare, and are required to offer the same benefits as provided by Original Medicare Part A and Part B. MA Plans are able to use their own coverage restrictions, rules, and costs as approved by Medicare. In many cases Medicare Advantage plans will incorporate additional coverage such as  prescription drugs, routine vision or dental care, hearing checkups, and wellness programs. To opt into a Medicare Advantage plan, you must first have Original Medicare Part A and Part B. and must live in the service area where the Medicare Advantage plan is offered.

Medicare Part A

Medicare is a federal health insurance program administered by the Centers for Medicare and Medicaid Services, with enrollment handled by Social Security. It benefits those who are 65 or older, as well as  people with end-stage renal disease and some younger people with disabilities. Part A (hospital insurance) refers to coverage provided for inpatient hospital stays, as well as hospice care, skilled nursing facility care, and some home health care.

Medicare Part B

Medicare is a federal health insurance program administered by the Centers for Medicare and Medicaid Services with enrollment handled by Social Security . It benefits those who are 65 or older, as well as  people with end-stage renal disease and some younger people with disabilities. Part B (medical insurance) refers to coverage provided for physician’s services, as well as medical supplies, preventive services, and outpatient hospital care.

Medicare Part C

Medicare is a federal health insurance program administered by the Centers for Medicare and Medicaid Services. Part C (Medicare Advantage) refers to plans that can be purchased from private insurers  approved by Medicare. (See Medicare Advantage)

Medicare Part D

Medicare is a federal health insurance program administered by the Centers for Medicare and Medicaid Services. It benefits those who are 65 or older, as well as  people with end-stage renal disease and some younger people with disabilities. Part D refers to optional coverage for prescription drugs that can be purchased from private insurance companies at an additional cost.

Medicare Summary Notice (MSN)

A notice you get after the doctor, other health care provider, or supplier files a claim for Part A or Part B services in Original Medicare. It explains what the doctor, other health care provider, or supplier billed for, the Medicare-approved amount, how much Medicare paid, and what you must pay.

Medicare Supplemental Insurance

Also known as Medigap, supplemental coverage that you can purchase from private insurance companies for a monthly premium to help pay for Medicare-approved services, including deductibles, copays, and coinsurance, that Original Medicare does not.

Original Medicare

Original Medicare describes the federal fee-for-service health insurance program administered by the Centers for Medicare and Medicaid Services(CMS). It combines Part A (hospital insurance) and Part B (medical insurance) and benefits those who are 65 or older, as well as  people with end-stage renal disease (ESRD), amyotrophic lateral sclerosis (ALS), and some younger people with disabilities. Every contracted service has a pre-approved amount that Medicare pays, after which you pay your share.

Out-of-Network Benefits

Benefits that may be covered by Medicare Advantage plans for health care services received by providers outside of the plan’s approved, in-network. Out-of-network services may cost you more.

Out-of-pocket costs

Health or prescription drug costs (deductibles, copays, and coinsurance) that you must pay on your own because they aren’t covered by Medicare or other insurance.

Preferred Provider Organization (PPO) Plan

A type of health plan that allows you to pay a lower cost for using physicians, hospitals, and providers that are in-network but permit youo use out-of-network providers at an additional cost.


The monthly fee that you pay to your insurance company, health care plan, or to Medicare for your coverage.

Preventive services

Health care to prevent illness or detect illness at an early stage, when treatment is likely to work best (for example, preventive services include Pap tests, flu shots, and screening mammograms).

Primary care doctor

The doctor you see first for most health problems. He or she makes sure you get the care you need to keep you healthy. He or she also may talk with other doctors and health care providers about your care and refer you to them. In many Medicare Advantage Plans, you must see your primary care doctor before you see any other health care provider.

Prior authorization

Approval that you must get from a Medicare drug plan before you fill your prescription in order for the prescription to be covered by your plan. Your Medicare drug plan may require prior authorization for certain drugs.

Private Fee-for-Service (PFFS) Plan

A type of health coverage available as a Medicare Advantage plan that permits you to seek service from any physician or facility that agrees to your plan’s payment terms and agrees to provide treatment. The amount that you pay for service is detailed within your plan documents.



A written order required by some Medicare Advantage health plans for medical services not provided by your primary care physician. A referral, obtained directly from your primary care physician, is usually required to have your health plan pay for a visit to a specialist or for services such as a vision examination.

State Health Insurance Assistance Program (SHIP)

A state program that gets money from the federal government to give free local health insurance counseling to people with Medicare.

Special Enrollment Period for Part B

The special enrollment period (SEP) for Part B  provides the opportunity to enroll in Medicare Part B if you did not enroll during your Initial Enrollment Period because you had group health coverage provided by an employer or union, or volunteered internationally for at least 12 months with a qualified service. Employer health plan coverage must be based on your current employment or the current employment of a spouse or family member at the time you first became eligible for Medicare. Coverage must remain continuous with no more than eight consecutive months of lapses from first becoming eligible for Medicare until Medicare enrollment during the SEP; neither COBRA or retirement coverage qualifies.

This special enrollment period lasts for eight months after termination of your employment or loss of employer coverage. However, you can enroll in Medicare Part B at any time you are still covered by a qualified plan based on your current employment.

Special Needs Plan (SNP)

A type of Medicare Advantage plan designed for beneficiaries who have a chronic illness such as diabetes, or who need specialized care (including long-term or institutional level care), or who are entitled to both Medicare and Medicaid. Beneficiaries can be eligible under more than one type of special need.


Urgently Needed Care

Urgently needed care describes care that is needed right away to treat a sudden illness or injury that is not life threatening. If you need this care when you are out of your plan’s area and cannot be seen by your primary care physician,your health plan will pay for it.

Waiting Period

The period of time that an enrollee in a Medigap or Medicare Advantage plan is required to wait before their coverage begins. In most cases, waiting periods are imposed if you have a pre-existing condition and have not had creditable coverage for a specified period of time. The time prior to a special enrollment date cannot be counted as part of a waiting period. Waiting period days do not count as a significant break in coverage and they cannot be counted towards creditable coverage unless there is other creditable coverage at that time.

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