Health Coverage Terms Every American Should Know

Why the terminology matters

Health insurance paperwork uses a consistent set of terms that determine what you pay, when you pay it, and what your plan will or will not cover. Misreading even one term can lead to unexpected bills. This reference explains the most common ones in plain language so you can read a plan document with confidence.

For a broader walkthrough of how coverage works, see Health Insurance Decoded, which covers the full picture for people new to the process.

Cost-sharing terms

Cost-sharing describes the portion of medical expenses you pay yourself, separate from what your insurer covers.

Premium is the fixed monthly amount you pay to keep your plan active, whether or not you use any care that month.

Deductible is the amount you pay out of pocket for covered services before your insurer begins paying its share. A $2,000 deductible means you cover the first $2,000 in eligible costs each plan year.

Copay is a flat fee you pay at the time of a specific service, such as $30 for a primary care visit. Coinsurance is a percentage split: if your plan covers 80% of a service after the deductible, you pay the remaining 20%. For a detailed breakdown of how these three interact, see Deductibles, Copays, and Coinsurance Explained.

Out-of-pocket maximum is the most you will pay for covered services in a plan year. Once you reach that limit, your insurer pays 100% of covered costs for the rest of the year. Premiums do not count toward this cap.

Coverage and network terms

Network refers to the group of doctors, hospitals, and other providers that have a contract with your insurer. Seeing an in-network provider generally costs less than seeing one outside the network.

Primary care physician (PCP) is the doctor who manages routine care and, in some plan types, must provide a referral before you see a specialist.

Referral is written approval from your PCP to see a specialist. Some plan types require it; others do not.

Prior authorization means your insurer must approve a treatment, procedure, or prescription before you receive it. Without approval, the insurer may deny the claim entirely. If a provider recommends a service that requires prior authorization, confirm the approval is in place before the appointment.

Formulary is your plan's list of covered prescription drugs, organized into tiers that affect your copay or coinsurance. A drug not on the formulary may not be covered, or may require a separate exception process.

Plan type also shapes these rules. An HMO (Health Maintenance Organization) typically requires a PCP and referrals; a PPO (Preferred Provider Organization) generally allows direct specialist access. To understand how plans are structured in the federal and state Marketplaces, see Understanding the Health Insurance Marketplace.

Claims and enrollment terms

Explanation of Benefits (EOB) is a statement your insurer sends after a claim. It shows what was billed, what the insurer paid, and what you owe. An EOB is not a bill, though a bill from the provider often follows.

Open enrollment is the annual window during which you can sign up for, change, or drop a health plan. Outside this window, changes are generally only allowed if you experience a qualifying life event such as losing other coverage or having a child.

Special enrollment period (SEP) is a time-limited window triggered by a qualifying life event that lets you enroll or make changes outside open enrollment.

COBRA is a federal provision that lets you continue employer-sponsored coverage for a limited time after leaving a job, though you typically pay the full premium yourself, including the portion your employer previously covered.

Several factors beyond the plan type affect what you ultimately pay each year. Factors that affect health coverage costs covers the full range, from plan tier to geographic location.

This article is for general informational purposes only and does not constitute medical, legal, or financial advice. Coverage terms, costs, and rules vary by plan and insurer. Read your plan documents carefully and consult a licensed insurance professional for guidance specific to your situation.