Health insurance glossary
26 health insurance terms defined in plain English. Each one links to the guide that explains it in depth.
A
- Allowed amount
- The maximum price your health plan has agreed to pay for a covered service. In-network providers can't bill you for more than this. Learn more
B
- Balance billing
- When an out-of-network provider bills you for the difference between their charge and what your plan paid. The No Surprises Act bans it in many emergency and surprise situations. Learn more
- Bronze, Silver, Gold and Platinum
- The ACA's metal tiers. They describe how costs are split between you and the plan, not the quality of care. Bronze has the lowest premiums and highest costs when you get care; Platinum is the opposite. Learn more
C
- COBRA
- A federal law that lets you keep your employer's group health plan for a limited time after leaving a job or losing eligibility, usually by paying the full premium plus a small fee. Learn more
- Coinsurance
- Your share of a covered bill as a percentage, such as 20%, which you pay after meeting your deductible. The plan pays the rest until you reach your out-of-pocket maximum. Learn more
- Copay
- A flat amount you pay for a covered service, such as $30 for a primary care visit or $15 for a generic prescription. Learn more
- Cost-sharing reductions
- Extra savings on Silver Marketplace plans for people with lower incomes. They lower your deductible, copays and out-of-pocket maximum. Learn more
D
- Deductible
- The amount you pay for covered care each plan year before your plan starts paying its share. Many plans cover preventive care and some copay services before the deductible. Learn more
E
- Explanation of benefits (EOB)
- A statement from your health plan showing what a provider charged, what the plan paid and what you may owe. It is not a bill. Learn more
F
- Formulary
- Your plan's list of covered prescription drugs, usually grouped into tiers that set how much you pay. Learn more
- FSA (flexible spending account)
- An employer account that lets you set aside pre-tax money for medical costs. Most of the money must be used within the plan year. Learn more
H
- HDHP (high-deductible health plan)
- A plan with a deductible that meets IRS minimums. Enrolling in a qualifying HDHP is what makes you eligible to contribute to an HSA. Learn more
- HMO
- Health maintenance organization: a plan that covers care only from its network (except emergencies) and usually requires a primary care doctor and referrals to see specialists. Learn more
- HSA (health savings account)
- A tax-advantaged savings account paired with a qualifying high-deductible plan. The money is yours to keep, rolls over every year and can be invested. Learn more
I
- In-network
- Doctors, hospitals and pharmacies that have a contract with your health plan. You pay much less when you use them. Learn more
O
- Open enrollment
- The yearly window to sign up for or change a health plan without a qualifying life event. For HealthCare.gov states, open enrollment for 2027 coverage runs November 1, 2026 to January 15, 2027 (enroll by December 15 for coverage starting January 1). Learn more
- Out-of-network
- Providers without a contract with your plan. Depending on your plan, care from them may be covered at a higher cost or not covered at all. Learn more
- Out-of-pocket maximum
- The most you will pay for covered, in-network care in a plan year, counting deductibles, copays and coinsurance. After you reach it, the plan pays 100% of covered costs. Premiums don't count toward it. Learn more
P
- PPO
- Preferred provider organization: a plan that lets you see in-network and out-of-network providers without referrals, with lower costs in-network. Premiums are usually higher than an HMO. Learn more
- Preventive care
- Screenings, vaccines and checkups that ACA-compliant plans must cover at no cost when you use an in-network provider. Learn more
- Prior authorization
- Approval your plan requires before it will cover certain services or drugs. Without it, the plan may refuse to pay. Learn more
Q
- Qualifying life event
- A change such as losing coverage, moving, marriage or having a baby that opens a special enrollment period, usually 60 days, to enroll outside open enrollment. Learn more
S
- Special enrollment period
- A window outside open enrollment, triggered by a qualifying life event, when you can sign up for or change health coverage. Learn more
- Summary of Benefits and Coverage (SBC)
- A standardized document every health plan must provide that lists the plan's deductible, out-of-pocket limit, copays and coinsurance in the same format, so plans are easy to compare. Learn more