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%.

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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

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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

In that case, the particulars of how each medication is covered—whether it’s a copay or coinsurance, for example—don’t matter.

From Barron's • Mar. 5, 2026

An employer could have a health plan that pays for expensive drugs with 20% employee coinsurance.

From The Wall Street Journal • Nov. 13, 2025

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