Insurance
Insurance is a mechanism for transferring risk by pooling it. A person or entity buys insurance to transfer their risk of loss to the insurer in exchange for a fee, the premium. The insurer assesses the probability of loss and combines many such exposures together to pool the risk. If an insurable loss occurs then the insurer is contractually bound to pay.
Related term: carrier, insurance policy, reinsurance
Here are some types of insurance: