What is Casualty Insurance?

Legal Definition
Casualty insurance is a problematically defined term which broadly encompasses insurance not directly concerned with life insurance, health insurance, or property insurance.

Casualty insurance is mainly liability coverage of an individual or organization for negligent acts or omissions. However, the term has also been used for property insurance, aviation insurance, boiler and machinery insurance, and glass and crime insurance. It may include marine insurance for shipwrecks or losses at sea, fidelity and surety insurance, earthquake insurance, political risk insurance, terrorism insurance, fidelity and surety bonds.

One of the most common kinds of casualty insurance today is automobile insurance. In its most basic form, automobile insurance provides liability coverage in the event that a driver is found "at fault" in an accident. This can cover medical expenses of individuals involved in the accident as well as restitution or repair of damaged property, all of which would fall into the realm of casualty insurance coverage.

If coverage were extended to cover damage to one's own vehicle, or against theft, the policy would no longer be exclusively a casualty insurance policy.
-- Wikipedia
Legal Definition
Insurance covering losses designated by legal process, due to damage or injury to a person or property.
Legal Definition
This term is generally used as equivalent to "accident" insurance. See State v. Federal Inv. Co.., 48 Minn. 110, 50 N. W. 1028. But in some states it means insurance against accidental injuries to property, as distinguished from accidents resulting in bodily injury or death. See Employers' Liability Assur. Co.rp. v. Merrill, 155 Mass. 404, 29 N. E. 529.
-- Black's Law Dictionary