Major medical insurance is a type of insurance that provides coverage for major medical expenses. There are many synonyms for major medical insurance, including catastrophic health insurance, high-deductible health insurance, and major medical coverage. Catastrophic health insurance provides coverage for medical emergencies, such as accidents or serious illnesses, and typically has a high deductible. High-deductible health insurance is a type of insurance that has a high deductible, meaning that the insured must pay a significant portion of the medical expenses before the insurance kicks in. Major medical coverage is a type of insurance that provides coverage for major medical expenses, such as hospitalization, surgery, and chemotherapy.