Plain definitions
Medicare glossary, in plain English.
A short glossary of the Medicare terms you actually hear when comparing plans.
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A–G
- AEP (Annual Enrollment Period)
- October 15 to December 7. The main window to switch plans. More.
- Coinsurance
- Your share of cost as a percentage (often 20%).
- Copay
- A flat fee per service.
- Coverage gap (donut hole)
- Historical Part D phase where you paid more for drugs. More.
- Creditable coverage
- Other coverage at least as good as Medicare, keeps you out of late penalties.
- Deductible
- Amount you pay before coverage starts.
- Formulary
- The list of drugs your Part D plan covers, organized by tier. More.
H–O
- HMO
- Network plan that usually requires you to stay in network. More.
- IEP (Initial Enrollment Period)
- The 7 months around your 65th birthday. More.
- IRMAA
- Income-Related Monthly Adjustment Amount, a surcharge on Part B and D for higher-income enrollees. More.
- MA OEP
- Medicare Advantage Open Enrollment Period, January 1 to March 31.
- Medigap
- Medicare Supplement Insurance. Pays your share of Original Medicare cost. More.
P–Z
- Part A
- Hospital insurance. More.
- Part B
- Outpatient and doctor insurance. More.
- Part C
- Medicare Advantage. More.
- Part D
- Prescription drug coverage. More.
- PPO
- Plan that allows out-of-network care at higher cost.
- Prior authorization
- Plan approval required before certain services. More.
- SNP (Special Needs Plan)
- An Advantage plan for specific conditions, dual eligibility, or institutional needs. More.
- Star Rating
- Medicare's 1–5 scale for plan quality. More.