Definition: The term "co-insurance" refers to a system where one party or group pays for the medical expenses incurred by another party, even if they do not have any insurance coverage themselves. This can be useful in situations where multiple parties are involved in a legal dispute involving an individual with multiple medical bills. For example, if a couple has two children who each have medical needs, they may choose to pay for part of the cost of those healthcare services together instead of covering all costs themselves. The specific definition of "co-insurance" can vary depending on the context and laws in place in a given location, but generally refers to the arrangement where one party (the co-insurer) pays for an individual's medical bills rather than paying out-of-pocket.