A written amendment as to the coverage of an existing life or health insurance policy, usually as certifying additional and specific coverage.
For example, a health insurance policy might exclude psychological illness but offer it as a rider at extra cost.
Traditionally, an amendment or modification of a property or liability insurance policy is referred to as an endorsement but this distinction is becoming blurred with the frequent use by the Courts and the industry of the term "rider" to refer to any add-on of coverage not otherwise included in a general policy, including in reference to liability or property.