coinsurance

American  

[koh-in-shoor-uhns, -shur-] / ˌkoʊ ɪnˈʃʊər əns, -ˈʃɜr- /

noun

1. insurance underwritten jointly with another or others.

2. a form of property insurance in which an insurer assumes liability only for that proportion of a loss which the amount of insurance bears to a specified percentage of the value of the property.

3. 1. a form of health insurance in which the insured party contributes a specified percentage of the total cost of medical expenses after a deductible has been reached.

   2. the percentage contributed by the insured party.

      My coinsurance is 20%.

---

coinsurance British  

/ -ˈʃɔː-, ˌkəʊɪnˈʃʊərəns /

noun

1. a method of insurance by which property is insured for a certain percentage of its value by a commercial insurance policy while the owner assumes liability for the remainder

2. joint insurance held by two or more persons

---

Etymology

Origin of coinsurance

First recorded in 1885–90; co- + insurance

Example Sentences

You will likely have health challenges; Medicare premiums, deductibles and coinsurance; emergency house repairs; and one or both of you may even require nursing-home care.

From MarketWatch • Apr. 1, 2026

Most of those who remained in ACA plans reported larger out-of-pocket healthcare expenses in the form of higher copays, coinsurance or deductibles, according to the survey from health-research nonprofit KFF.

From The Wall Street Journal • Mar. 19, 2026

That includes copayments, coinsurance, and deductibles but excludes monthly premium costs.

From Barron's • Mar. 5, 2026

There might not be an upfront premium, but there could be copays and coinsurance.

From MarketWatch • Nov. 5, 2025

In fact, insurance companies typically set coinsurance and copay amounts based on a drug's original list price, not the negotiated price.

From Salon • Nov. 22, 2024