A clause in certain property insurance policies which provides for the application of a penalty for partial losses when owners of property fail to insure, as a minimum, to the percentage of the value of such property as specified by the insurer, e.g., 80, 90 or 100 percent.

Coinsurance is a cost-sharing requirement where you are responsible for paying a certain percentage and the insurance company will pay the remaining percentage of the covered medical expenses after your deductible is met. For a health insurance plan with 20% coinsurance, once the deductible is met, the insurance company will pay 80% of the covered expenses while you pay the remaining 20% until your out-of-pocket limit is reached for the year. See similar questions...