Medicare Glossary

Medicare can sometimes feel like learning a new language. With so many acronyms, plan types, and industry terms—like Part A, Part B, MAPD, PDP, and more—it’s easy to feel overwhelmed when trying to understand your coverage options.

This page is designed to help simplify the terminology. If you come across a word, phrase, or acronym that doesn’t make sense, you can reference this guide for clear, straightforward explanations of common Medicare terms. Our goal is to make Medicare easier to understand so you can feel confident about the decisions you make regarding your healthcare coverage.

Medicare Program Verbiage

  • Medicare
    A federal health insurance program primarily for individuals age 65 and older, as well as certain younger individuals with disabilities or qualifying medical conditions.

  • Medicare Part A (Hospital Insurance)
    Covers inpatient hospital stays, skilled nursing facility care, hospice care, and limited home health services. Many beneficiaries receive Part A premium-free if they or their spouse worked 40 quarters (10 years) paying Medicare taxes.

  • Medicare Part B (Medical Insurance)
    Covers doctor visits, outpatient services, preventive care, diagnostic testing, mental health services, durable medical equipment, and many medically necessary services. Beneficiaries pay a monthly premium that can vary depending on income.

  • Medicare Part C (Medicare Advantage)
    Private health plans approved by Medicare that bundle Part A and Part B coverage and often include additional benefits such as dental, vision, hearing, fitness programs, and transportation.

  • Medicare Part D (Prescription Drug Coverage)
    Coverage for outpatient prescription medications offered through private insurance companies approved by Medicare.

  • Original Medicare
    The traditional Medicare program administered by the federal government, consisting of Part A and Part B coverage.

Medicare Advantage Plan Types

  • C-SNP (Chronic Condition Special Needs Plan)
    A Medicare Advantage plan designed for beneficiaries with specific chronic conditions, such as diabetes, heart disease, or COPD. Care coordination focuses on managing the specific condition.

  • D-SNP (Dual Eligible Special Needs Plan)
    A Medicare Advantage plan designed for individuals who qualify for both Medicare and Medicaid, coordinating benefits between the two programs and often including additional cost assistance and benefits.

  • HMO (Health Maintenance Organization)
    A plan type requiring members to use in-network providers for most services and typically requiring referrals from a Primary Care Provider (PCP) to see specialists.

  • HMO-POS (HMO Point of Service)
    A variation of an HMO plan that allows limited out-of-network services, typically at higher out-of-pocket costs.

  • I-SNP (Institutional Special Needs Plan)
    A Medicare Advantage plan designed for individuals living in nursing homes or requiring long-term institutional level care.

  • MAPD (Medicare Advantage Prescription Drug Plan)
    A Medicare Advantage plan that includes prescription drug coverage (Part D) in addition to medical benefits.

  • MA (Medicare Advantage)
    Private insurance plans that replace Original Medicare by providing Part A and Part B coverage through a single coordinated plan.

  • MSA (Medical Savings Account)
    A high-deductible Medicare Advantage plan combined with a medical savings account funded by the plan for healthcare expenses.

  • PFFS (Private Fee-for-Service)
    A Medicare Advantage plan where the plan determines how much it pays providers and how much the beneficiary must pay. Some plans have networks while others allow broader provider acceptance.

  • POS (Point of Service)
    A plan structure that allows members to receive care outside the provider network, usually with higher copays or coinsurance.

  • PPO (Preferred Provider Organization)
    A plan type offering greater flexibility, allowing members to visit out-of-network providers without referrals, usually at higher costs.

  • SNP (Special Needs Plan)
    Medicare Advantage plans designed for specific groups of beneficiaries, including those with chronic conditions, dual eligibility, or institutional care needs.

Provider Structure & Verbiage

  • Network
    The group of doctors, hospitals, pharmacies, and providers contracted with a health plan to provide services at negotiated rates.

  • PCP (Primary Care Provider)
    The main doctor responsible for coordinating a beneficiary’s healthcare, managing overall treatment and providing referrals to specialists in certain plan types.

  • Referral
    A formal authorization from a Primary Care Provider allowing a patient to see a specialist, required in many HMO-style plans.

  • Urgent Care
    Non-emergency medical care needed quickly, typically for conditions such as minor injuries, infections, or illnesses.

Prescription Drug Coverage & Formularies

  • Formulary
    The list of prescription drugs covered by a Medicare Part D or MAPD plan. Each plan’s formulary determines which medications are covered and what tier they fall under.

  • Preferred Pharmacy
    Pharmacies within a plan’s network that offer lower prescription copays compared to standard pharmacies.

  • Step Therapy
    A cost-management strategy requiring beneficiaries to try lower-cost medications first before a plan covers more expensive alternatives.

Prescription Drug Tier Levels

Prescription medications are categorized into tiers that determine cost sharing:

  • Tier 1 – Preferred Generic Drugs
    Lowest cost medications, typically common generic prescriptions.

  • Tier 2 – Generic Drugs
    Standard generic medications with slightly higher copays than Tier 1.

  • Tier 3 – Preferred Brand Drugs
    Brand-name medications preferred by the plan, with moderate copayments or coinsurance.

  • Tier 4 – Non-Preferred Brand Drugs
    Brand-name medications not preferred by the plan, usually with higher out-of-pocket costs.

  • Tier 5 – Specialty Drugs
    High-cost medications used to treat complex or rare conditions, such as cancer therapies or specialty biologic medications.

  • Tier 6 – Select Care Drugs (Plan-Specific)
    Some plans include a low-cost maintenance medication tier for common chronic condition treatments like blood pressure or cholesterol medications.

Enrollment Periods

  • AEP (Annual Enrollment Period)
    Occurs October 15 – December 7 each year. Beneficiaries can join, switch, or drop Medicare Advantage or Part D plans, with changes effective January 1.

  • IEP (Initial Enrollment Period)
    The 7-month window surrounding a person’s 65th birthday when they first become eligible to enroll in Medicare.

  • OEP (Medicare Advantage Open Enrollment Period)
    Occurs January 1 – March 31 each year and allows individuals already enrolled in a Medicare Advantage plan to switch plans or return to Original Medicare.

  • SEP (Special Enrollment Period)
    A period outside normal enrollment windows allowing beneficiaries to change coverage due to qualifying life events, such as moving or losing other coverage.

Costs & Cost-Sharing

  • Coinsurance
    The percentage of costs a beneficiary pays after meeting a deductible, such as 20% for many services under Medicare Part B.

  • Copayment (Copay)
    A fixed dollar amount paid for a service, such as a doctor visit or prescription medication.

  • Deductible
    The amount a beneficiary must pay before insurance begins covering certain services.

  • MOOP (Maximum Out-of-Pocket)
    The maximum amount a beneficiary must pay for covered medical services in a Medicare Advantage plan each year. After this limit is reached, the plan pays 100% of covered services.

Medicaid Verbiage

  • Extra Help (Low-Income Subsidy – LIS)
    A federal assistance program that helps individuals with limited income pay for Medicare Part D prescription drug costs, including premiums, deductibles, and copays.

  • Medicaid
    A state and federally funded program providing healthcare coverage for individuals with limited income and resources. Some people qualify for both Medicare and Medicaid.

Additional Medicare Terminology

  • Assignment (Medicare Assignment)
    When a provider accepts the Medicare-approved amount as full payment for services, typically resulting in lower costs for the beneficiary.

  • Appeal
    A formal request to reconsider a coverage decision or payment denial made by Medicare or a Medicare plan.

  • Coverage Determination
    A decision made by a Part D plan regarding whether a medication is covered and how much the beneficiary must pay.

  • DME (Durable Medical Equipment)
    Medically necessary equipment prescribed by a doctor for use in the home, such as walkers, oxygen equipment, or hospital beds.

  • Late Enrollment Penalty (LEP)
    A permanent premium increase applied to Part B or Part D if a beneficiary delays enrollment without having other creditable coverage.

  • Part B Giveback (Social Security Giveback)
    A benefit offered by some Medicare Advantage plans that reduces a beneficiary’s monthly Part B premium, often increasing their Social Security payment or reducing their billed premium.

  • Prior Authorization
    A requirement that certain services, procedures, or medications receive approval from the plan before they are covered.

  • Skilled Nursing Facility (SNF)
    A facility providing short-term skilled nursing or rehabilitation care following a hospital stay.