Reference
The Medicare glossary, in plain English
Every industry has vocabulary that exists mainly to sound official. These are the terms that actually change what you pay or when you can act, defined without the jargon.
Figures reviewed for 2026
38 terms
A
- Annual Election Period
- The fall window, October 15 through December 7, when anyone on Medicare can change a drug plan or a Medicare Advantage plan for the following January.
- Assignment
- A provider’s agreement to accept the Medicare-approved amount as payment in full. Providers who take assignment cannot bill you above that amount beyond the standard coinsurance.
- Attained-age rating
- A premium structure where the price rises as you get older. It starts cheaper than other methods and becomes more expensive over time.
B
- Benefit period
- The way Part A measures a hospital stay, beginning with admission and ending after sixty days without inpatient care. Each new benefit period brings a fresh deductible.
C
- Coinsurance
- Your share of a covered service, expressed as a percentage. Medicare typically pays eighty percent and you owe the other twenty.
- Community-rated
- A premium structure where everyone in a state pays the same rate for the same policy regardless of age. Increases are shared across the whole group.
- Copayment
- A flat dollar amount you pay for a service or a prescription, rather than a percentage of the cost.
- Creditable coverage
- Drug coverage at least as good as standard Part D. Holding it without interruption protects you from the late enrollment penalty if you later join a Part D plan.
D
- D-SNP
- A Dual Eligible Special Needs Plan: a Medicare Advantage plan available only to people who have both Medicare and Medicaid.
- Deductible
- The amount you pay before insurance begins paying its share. Part B has an annual deductible; Part A has one per benefit period.
- Dual eligible
- A person enrolled in both Medicare and Medicaid, which usually means Medicare pays first and Medicaid picks up much of what remains.
E
- Excess charge
- The amount a non-participating provider may bill above the Medicare-approved amount, capped at fifteen percent. Only Medigap Plans F and G cover it.
- Extra Help
- Also called the Low-Income Subsidy. A federal program that reduces Part D premiums, deductibles, and copays for people with limited income and resources.
F
- Formulary
- The list of prescriptions a drug plan covers, organized into tiers that determine what you pay. It can change every January.
G
- Guaranteed issue rights
- Situations in which an insurer must sell you a Medigap policy without health questions, such as losing employer coverage or using the trial right.
I
- Initial Enrollment Period
- Your first chance to sign up for Medicare, a seven-month window around the month you turn sixty-five or first become eligible.
- IRMAA
- The income-related monthly adjustment amount: an extra charge on Part B and Part D premiums for higher earners, based on a tax return from two years earlier.
- Issue-age rating
- A premium structure where the price is set by your age when you first enroll and future increases are not tied to aging.
M
- Medicaid
- A joint federal and state program for people with limited income, separate from Medicare. It can also help pay Medicare premiums and cost sharing.
- Medicare Advantage
- A private plan that delivers your Part A and Part B benefits, usually through a network, and often includes drug coverage and extra benefits.
- Medicare Savings Program
- State-administered help that pays the Part B premium and, for some enrollees, Medicare cost sharing as well.
- Medigap
- A standardized supplement policy sold by private insurers that pays some or all of your Original Medicare cost sharing.
N
- Network
- The set of doctors, hospitals, and pharmacies a plan contracts with. Care outside it costs more or is not covered at all.
O
- Original Medicare
- The government-administered program itself, made up of Part A for hospital care and Part B for medical care, usable with any provider that accepts Medicare.
P
- Part A
- The hospital half of Medicare: inpatient stays, skilled nursing after a qualifying admission, hospice, and limited home health.
- Part B
- The medical half of Medicare: physician visits, outpatient care, equipment, imaging, and preventive services, in exchange for a monthly premium.
- Part C
- The statutory name for Medicare Advantage. It is not a separate benefit, only a different way of receiving Parts A and B.
- Part D
- Prescription drug coverage, sold as a stand-alone policy or included inside a Medicare Advantage plan.
- PPO
- A plan type that allows out-of-network care at a higher cost share, usually without a referral requirement.
- Premium
- The monthly amount you pay to keep coverage in force, separate from any deductible, copay, or coinsurance you owe for care.
- Prior authorization
- A requirement that the plan approve certain services or drugs before they happen. A denial can be appealed with clinical documentation.
Q
- QMB
- Qualified Medicare Beneficiary: the broadest Medicare Savings Program, which covers the Part B premium and Medicare cost sharing.
S
- SEP
- A Special Enrollment Period that lets you change coverage outside the standard windows, usually triggered by losing other coverage or moving.
- Skilled nursing facility
- A facility providing daily skilled care such as therapy or wound treatment, covered by Part A for up to one hundred days after a qualifying hospital stay.
- Step therapy
- A plan rule requiring you to try a lower-cost drug first and show it did not work before it will cover a more expensive one.
T
- Trial right
- A federal protection allowing a first-time Medicare Advantage enrollee to return to Original Medicare and buy a Medigap policy without health questions within twelve months.
U
- Underwriting
- The health review an insurer performs before issuing a Medigap policy outside a guaranteed issue situation.
W
- Waiting period
- A stretch of time before a policy begins paying benefits. Insurers cannot impose one during a guaranteed issue situation.
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