Medicare Term Glossary

A plain-language reference for the words, letters, and acronyms that come up most in Medicare conversations.

A

Annual Enrollment Period (AEP)

October 15 – December 7 each year, when you can switch Medicare Advantage or Part D plans for the following year.

B

Beneficiary

A person enrolled in Medicare and eligible to receive its benefits.

C

Coinsurance

The percentage of a covered service's cost you pay after meeting your deductible.

C

Copayment (Copay)

A fixed dollar amount you pay for a covered service, such as $20 for a doctor visit.

D

Deductible

The amount you pay out of pocket before your plan begins to pay its share.

F

Formulary

The list of prescription drugs a Part D or Medicare Advantage plan covers.

G

General Enrollment Period

January 1 – March 31, for people who missed their Initial Enrollment Period and don't qualify for a Special Enrollment Period.

I

Initial Enrollment Period (IEP)

The seven-month window around your 65th birthday when you first become eligible to enroll in Medicare.

M

Medicare Supplement

Private insurance, sold alongside Original Medicare, that helps pay deductibles, copayments, and coinsurance Original Medicare leaves behind.

M

Medicare Advantage (Part C)

A private-plan alternative to Original Medicare that bundles hospital, medical, and often drug and extra benefits.

N

Network

The group of doctors, hospitals, and pharmacies a plan has contracted with for services, often at a lower cost.

O

Original Medicare

The federal government's Part A and Part B coverage, as opposed to a private Medicare Advantage plan.

O

Out-of-Pocket Maximum

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

P

Premium

The amount you pay, usually monthly, to keep an insurance plan active.

P

Part A

Medicare's hospital insurance, covering inpatient stays, skilled nursing, and hospice care.

P

Part B

Medicare's medical insurance, covering doctor visits, outpatient care, and preventive services.

P

Part D

Medicare's optional prescription drug coverage, offered through private insurers.

S

Special Enrollment Period (SEP)

A window outside normal enrollment periods triggered by specific life events, like losing employer coverage or moving.

S

Medicare Supplement Open Enrollment Period

A six-month window starting when you're 65+ and enrolled in Part B, during which insurers can't deny you a Medicare Supplement policy for health reasons.

U

Underwriting

The process an insurer uses to evaluate health risk, which can affect approval or pricing outside protected enrollment windows.

Don't see the term you're looking for? Ask us directly — we're happy to explain anything in your plan documents too.

Still feels like a foreign language?

Bring your questions, your mail from Medicare, or your current plan — we'll translate it together.

Ask a Question