coinsurance

noun

co·​in·​sur·​ance ˌkō-ən-ˈshu̇r-ən(t)s 

 also  -ˈin-ˌshu̇r-

1

: joint assumption of risk (as by two underwriters) with another

2

: insurance (such as fire insurance) in which the insured is obligated to maintain coverage on a risk at a stipulated percentage of its total value or in the event of loss suffer a penalty in proportion to the deficiency

3

: health insurance in which the insured is required to pay a fixed percentage of the cost of medical expenses after the deductible has been paid and the insurer pays the remaining expenses

Coinsurance is not a new idea—Americans who grew up in the era before managed care will remember their parents paying 20% of the costs of office visits, tests, and prescriptions.

—Thomas H. Lee et al.

Examples of coinsurance in a Sentence

Recent Examples on the Web

Medical schools rarely teach students about deductibles, coinsurance, or out-of-pocket maximums. —Peter Ubel, Forbes.com, 29 May 2025

But since 2020, insurance companies have shifted most patients from flat co-pays to coinsurance. —Peter Ubel, Forbes.com, 23 Apr. 2025

Employers can also partner with their brokers and third-party administrators to advocate for network changes where high-performing providers are paid faster in exchange for lower rates and where there are no copayments or coinsurance for the member, which could limit bad debt. —Sara Ratner, Forbes.com, 16 Apr. 2025

Many also must pay coinsurance, which is a percentage of a total drug's cost. —Ken Alltucker, USA Today, 25 Apr. 2025

Word History

First Known Use

circa 1889, in the meaning defined at sense 1

Rhymes for coinsurance

• concurrence
• deterrence
• incurrence
• occurrence
• recurrence
• transference
• countertransference

Medical Definition

coinsurance

noun

co·​in·​sur·​ance ˌkō-ən-ˈshu̇r-ən(t)s, -ˈshər- also -ˈin-ˌshu̇r-, -ˌshər- 

: health insurance in which an insurer requires the insured to pay a fixed percentage of the cost of medical expenses after the deductible has been paid and with the insurer to pay the remaining expenses

Coinsurance is not a new idea—Americans who grew up in the era before managed care will remember their parents paying 20% of the costs of office visits, tests, and prescriptions.

—Thomas H. Lee et al., The New England Journal of Medicine

Legal Definition

coinsurance

noun

co·​in·​sur·​ance ˌkō-in-ˈshu̇r-əns, kō-ˈin-ˌshu̇r- 

1

: joint assumption of risk (as by two underwriters) with another

2

: insurance (as fire insurance) in which the insured is obligated to maintain coverage on a risk at a stipulated percentage of its total value or in the event of loss to suffer a penalty in proportion to the deficiency