Health insurance is insurance that covers the whole or a part of the risk of a person incurring medical expenses, spreading the risk over a large number of persons. By estimating the overall risk of health care and health system expenses over the risk pool, an insurer can develop a routine finance structure, such as a monthly premium or payroll tax, to provide the money to pay for the health care benefits specified in the insurance agreement. The benefit is administered by a central organization such as a government agency, private business, or not-for-profit entity.
Usage Note: Some people insist on maintaining a distinction between the words healthy and healthful. In this view, healthful means "conducive to good health" and is applied to things that promote health, while healthy means "possessing good health," and is applied solely to people and other organisms. Accordingly, healthy people have healthful habits. However, healthy has been used to mean "healthful" since the 1500s, as in this example from John Locke's Some Thoughts Concerning Education: "Gardening ... and working in wood, are fit and healthy recreations for a man of study or business." In fact, the word healthy is far more common than healthful when modifying words like diet, exercise, and foods, and healthy may strike many readers as more natural in many contexts. Certainly, both healthy and healthful must be considered standard in describing that which promotes health.