1. A provision in an insurance policy requiring the insured to pay a fixed percentage of covered losses, with the insurer paying the remainder.
Usage: Common in health insurance and property insurance
2. An arrangement in which two or more insurance companies jointly insure the same risk, each bearing a proportional share of the loss.
Usage: Used for large or complex risks

Examples

• Under the health plan's coinsurance clause, the patient pays 20% of the medical bill while the insurer covers 80%.
• The homeowner's policy includes a 10% coinsurance requirement for property damage claims.
• Multiple insurers agreed to coinsurance on the commercial building to spread the risk.
• After meeting her deductible, Sarah's coinsurance obligation was $500 per doctor visit.
• The coinsurance arrangement allowed the insurance company to manage its exposure on the large industrial project.
• Patients should understand their coinsurance percentage before scheduling expensive procedures.