Health Insurance Terminology Reference: 40 Terms Explained

Cost-Sharing Terms: What You Pay at the Point of Care

Health insurance shifts costs between the insurer and the enrollee through a set of structured mechanisms. Understanding each one is essential before you can judge whether a plan fits your budget.

Premium

The monthly amount you pay to maintain health coverage, regardless of whether you use any services. Premiums are separate from all other costs.

Deductible

The amount you pay out of pocket for covered services before your insurer starts sharing costs. For example, a $1,500 deductible means you cover the first $1,500 in eligible claims each plan year.

Copay (Copayment)

A fixed dollar amount you pay for a specific service — often $25 for a primary care visit or $50 for a specialist. Copays may apply before or after your deductible, depending on the plan.

Coinsurance

Your share of costs after the deductible is met, expressed as a percentage. With 20% coinsurance, you pay 20% of the allowed amount and the insurer pays 80%.

Out-of-Pocket Maximum

The most you'll pay for covered in-network services in a plan year. Once reached, the insurer pays 100% of covered costs for the remainder of the year.

Embedded vs. Aggregate Deductible

On family plans, an embedded deductible gives each member an individual limit inside the family total. An aggregate deductible requires the family as a whole to meet one combined threshold before any member's costs are shared.

For a deeper look at how these three cost-sharing layers interact, see Deductibles, Copays, and Coinsurance: What Each One Actually Costs You.

Plan Types and Network Terms

The structure of your plan determines which providers you can see, whether you need referrals, and how much you'll pay for going outside the network.

HMO (Health Maintenance Organization)

Requires you to choose a primary care physician (PCP) who coordinates all care. Referrals are needed for specialists, and out-of-network care is generally not covered except in emergencies.

PPO (Preferred Provider Organization)

Offers a broader network with no referral requirement. You can see out-of-network providers, but at a higher cost than in-network visits.

EPO (Exclusive Provider Organization)

Combines elements of both: no referrals needed, but coverage is restricted to a defined network — similar to an HMO in that out-of-network care (except emergencies) is not covered.

HDHP (High-Deductible Health Plan)

A plan with higher deductibles and lower premiums that qualifies for pairing with a Health Savings Account (HSA). IRS sets the minimum deductible thresholds each year.

In-Network Provider

A doctor, hospital, or facility that has a contract with your insurer to provide services at negotiated rates. Using in-network providers typically results in lower out-of-pocket costs.

Out-of-Network Provider

A provider without a contract with your insurer. You may pay significantly more or face balance billing unless federal or state protections apply.

Primary Care Physician (PCP)

A general or family practice physician who manages routine care and, in HMO plans, coordinates referrals to specialists.

Referral

A written order from your PCP authorizing you to see a specialist. Required under most HMO plans; not required under PPO or EPO plans.

Plan structures also matter for specialty coverage. Health Insurance Decoded provides a broader overview of how these plan types work in practice.

Coverage, Claims, and Policy Terms

These terms govern what your plan covers, how claims are processed, and what rights and limitations apply during and after enrollment.

Essential Health Benefits (EHBs)

Ten categories of services ACA-compliant plans must cover, including emergency services, hospitalization, maternity care, mental health, prescription drugs, and preventive care.

Preventive Care

Services like screenings, immunizations, and annual wellness visits that ACA-compliant plans must cover at no cost-sharing when delivered by an in-network provider.

Pre-existing Condition

A health condition that existed before a new coverage period begins. ACA Marketplace plans cannot deny coverage or charge higher premiums based on pre-existing conditions.

Qualifying Life Event (QLE)

A change in circumstance — such as marriage, the birth of a child, or loss of other coverage — that triggers a Special Enrollment Period outside the standard Open Enrollment window.

Special Enrollment Period (SEP)

A window outside Open Enrollment during which you may enroll in or change a health plan if you experience a qualifying life event.

COBRA

A federal law allowing workers and their dependents to continue employer-sponsored health coverage for a limited period after leaving a job or experiencing another qualifying event. The enrollee typically pays the full premium, which can be substantially higher than what employees pay.

Grace Period

A set number of days after a missed premium payment during which coverage remains active. If payment isn't made within the grace period, the insurer may cancel the policy.

Exclusion

A service, condition, or circumstance specifically not covered by a plan. Exclusions are listed in the plan documents and should be reviewed carefully before enrolling.

Rider

An optional addition to a base policy that modifies or expands coverage, sometimes for an additional premium. Common in supplemental or life insurance but less so in standard health plans.

Mental health coverage falls under Essential Health Benefits. For related terminology, see Mental Health Vocabulary: A Plain-Language Reference.

Accounts, Subsidies, and Administrative Terms

Beyond the plan itself, a range of accounts and financial mechanisms affect your total cost of coverage.

HSA (Health Savings Account)

A tax-advantaged account available to people enrolled in a qualifying HDHP. Contributions, growth, and withdrawals for qualified medical expenses are all tax-free. Unused funds roll over year to year.

FSA (Flexible Spending Account)

An employer-sponsored account that lets you set aside pre-tax dollars for qualified medical expenses. Unlike HSAs, FSAs generally have a use-it-or-lose-it rule, though some plans allow limited rollover.

HRA (Health Reimbursement Arrangement)

An employer-funded account that reimburses employees for qualified medical expenses. Unlike HSAs, HRAs are funded only by the employer and are not portable if you leave the job.

Premium Tax Credit

A federal subsidy available to eligible individuals and families who purchase coverage through the ACA Marketplace. The credit reduces monthly premiums based on income relative to the federal poverty level.

Cost-Sharing Reduction (CSR)

An ACA subsidy that lowers out-of-pocket costs — including deductibles and copays — for eligible lower-income enrollees in Silver-tier plans.

Actuarial Value

The percentage of total covered costs a plan pays on average across its enrollees. Bronze plans have a 60% actuarial value; Platinum plans have 90%. Higher actuarial value generally means lower out-of-pocket costs but higher premiums.

Medicaid

A joint federal-state program providing health coverage to eligible low-income individuals and families. Eligibility rules and covered services vary by state.

Medicare

A federal health insurance program primarily for people aged 65 and older, and for certain individuals with disabilities. Divided into Part A (hospital), Part B (outpatient), Part C (Medicare Advantage), and Part D (prescription drugs).

Utilization Review

An insurer's evaluation of whether a proposed or delivered service is medically necessary. Decisions can be appealed; many states require external review options.

Network Adequacy

A regulatory standard requiring that plans include a sufficient number and type of in-network providers to meet members' health needs within a reasonable geographic distance and wait time.

For a broader look at insurance terminology across policy types, see The Language of Insurance: A Glossary of Terms Every Policyholder Should Know. For life insurance policy document interpretation, see Reading a Life Insurance Policy Document Without Getting Lost.

This article provides general educational information about health insurance terminology and is not personalized insurance, financial, legal, or medical advice. Coverage terms, costs, and eligibility rules vary by plan, insurer, and state. Always read your plan documents carefully and consult a licensed insurance professional for guidance specific to your situation.