coinsurance

• co-insurance

From co- +‎ insurance.

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coinsurance (countable and uncountable, plural coinsurances)

1. (especially US) The joint assumption of risk between the insurer and the insured party.
2. (especially US, metonymic) The amount paid by the insured in accordance with this risk sharing.
   • 2021, Medicare & You 2022, Baltimore, MD: U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES : Centers for Medicare & Medicaid Services, page 6:

     For Part B-covered services, you usually pay 20% of the Medicare-approved amount after you meet your deductible. This is called your coinsurance.

3. (international) The joint assumption of risk between multiple insurers.

• coinsurer
• copayment
• deductible