Medicare Glossary

Understand the terms you'll encounter when signing up for Medicare.

Reviewed by Aaron Sims, Licensed Life & Health Agent since 2012

A–Z Medicare Terms

Medicare terminology, explained simply

Medicare comes with its own vocabulary. From deductibles and copays to enrollment periods and coverage gaps, we break down the key terms so you can make informed decisions about your healthcare.

18+ terms

Defined and regularly updated

B (1 terms)

Benefit Period

The time frame Medicare uses to measure your use of hospital and skilled nursing facility services.

C (2 terms)

Coinsurance

The percentage of costs you share with Medicare after meeting your deductible.

Copayment

A fixed dollar amount you pay for a covered health care service.

D (1 terms)

Deductible

The amount you pay out-of-pocket before your insurance begins to cover costs.

E (1 terms)

Extra Help

A Medicare program that helps people with limited income and resources pay for Part D prescription drug costs.

F (1 terms)

Formulary

A list of prescription drugs covered by a Medicare Part D or Medicare Advantage plan.

I (1 terms)

Initial Enrollment Period

The 7-month window around your 65th birthday when you can first sign up for Medicare.

M (6 terms)

Medicare Part A

Hospital insurance that covers inpatient hospital stays, skilled nursing facility care, hospice, and some home health care.

Medicare Part B

Medical insurance that covers doctor visits, outpatient care, preventive services, and durable medical equipment.

Medicare Part C

Medicare Advantage — private health plans that bundle Part A, Part B, and usually Part D into one plan.

Medicare Part D

Prescription drug coverage available through private plans approved by Medicare.

Medicare Savings Programs

State programs that help pay Medicare premiums and sometimes deductibles and coinsurance for people with limited income.

Medigap

Medicare Supplement Insurance policies sold by private companies to help pay for costs Original Medicare doesn't cover.

O (2 terms)

Open Enrollment Period

The annual window from October 15 to December 7 when you can change your Medicare Advantage or Part D plan.

Out-of-Pocket Maximum

The most you'll pay in a year for covered services in a Medicare Advantage plan before the plan covers 100% of costs.

P (2 terms)

Premium

The monthly amount you pay for Medicare or a private Medicare plan.

Prior Authorization

Approval required from your plan before you can get certain drugs or services covered.

S (1 terms)

Special Enrollment Period

A time outside of standard enrollment periods when you can sign up for or change Medicare coverage due to qualifying life events.