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

Medigap policies sit alongside traditional Medicare plans and are optional coverage designed to pay for uncovered costs like copayments, coinsurance, and deductibles.

From Barron's • Jun. 4, 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

However, critics say $1,000 or $1,500 deposited in a HSA won’t do much for someone who is paying $2,000 per month with 40% coinsurance and a $9,900 out-of-pocket maximum.

From MarketWatch • Jan. 24, 2026

Patients with deductibles or coinsurance then get hit with out-of-pocket costs tied to that inflated list price, while the rebate money flows back to insurers or employers to lower premiums for the broader pool.

From The Wall Street Journal • Dec. 12, 2025

This bill would require that patients pay coinsurance rates based on a drug's negotiated, discounted price, rather than on its full list price.

From Salon • Nov. 22, 2024