Health insurance, exactly what is it?

Health Insurance is a type of insurance coverage for individuals to help protect them against unexpected medical cost, coverage whereby the insurer pays the medical costs of the insured, if the insured becomes sick due to covered causes, or due to accidents. The insurer may be a private organization or a government agency.

Insurance coverage, is the equitable transfer of the risk of a potential loss, from one entity to another, in exchange for a premium, is a form of risk management primarily used when an investment is taken out specifically to reduce or cancel out the risk in another investment, usually against the risk of a contingent loss.

Insurer, in economics, is the company that sells the insurance.
Insured, The person or persons whose life or health is insured under an insurance policy. Also referred to as a "member."

Insurance rate/premium is a factor used to determine the amount the insured person or persons is responsible to pay in order to obtain coverage, the amount to be charged for a certain amount of insurance coverage.

Risk management, the practice of appraising and controlling risk.