Definition
In law, lightning functions as a descriptive and classificatory term rather than a term of art, appearing primarily in two contexts: (1) insurance law, where the scope of coverage for lightning-related losses is frequently disputed, and (2) tort and contract law, where a lightning strike may qualify as an act of God, affecting liability and excuse doctrines.
In insurance law, lightning refers to any sudden and violent discharge of electricity occurring in nature — whether cloud-to-earth, earth-to-cloud, or cloud-to-cloud — and the legal question typically turns on whether a given policy's coverage language extends to a particular type of electrical event and whether actual ignition or combustion is required to trigger a fire policy.
In tort and contract law, a lightning strike is a recognized instance of an act of God (vis maior): an event of natural origin, extraordinary in character, that could not have been anticipated or guarded against by reasonable care. This classification can excuse performance of contractual obligations or negate liability for damages caused.
Common Language
Modern common usage (Wiktionary): A flash of light produced by short-duration, high-voltage discharge of electricity within a cloud, between clouds, or between a cloud and the earth; also, any discharge of this kind.
Historical common usage (Webster's 1913): A discharge of atmospheric electricity, accompanied by a vivid flash of light, commonly from one cloud to another, sometimes from a cloud to the earth; the associated sound constitutes thunder.
The gap between common and legal meaning is largely one of precision and consequence rather than kind. Ordinary usage treats lightning as a natural phenomenon; legal usage treats it as a classification trigger — activating or defeating insurance coverage, allocating tort liability, or excusing contractual nonperformance. The legal questions are never about what lightning is, but about what it does within a doctrinal framework.
Common Confusion
Two recurring confusions appear in insurance contexts. First, courts and adjusters have disagreed about whether a "fire by lightning" clause in a policy requires actual combustion and ignition, or whether electrical damage without visible flame suffices. Anderson's entry reflects this directly: coverage for fire by lightning has been held not to extend to damage where there is no ignition. Second, the relationship between lightning and associated weather events — particularly tornadoes — creates coverage disputes. Expert testimony has been admitted to establish that lightning accompanying a tornado was the proximate cause of a loss, separating covered from uncovered damage within a single event.
Why It Matters in Research
Researchers working in insurance law should pay close attention to the precise policy language at issue in any historical source. Pre-twentieth-century fire policies frequently bundled "fire and lightning" as a single covered peril, but the scope of that bundling was inconsistently interpreted. Whether a policy required ignition was a live doctrinal question well into the twentieth century, and older cases should not be read as settling modern interpretive questions without checking later authority.
The act of God doctrine is a second research node. Lightning appears as a standard illustration in treatises on impossibility, frustration, and vis maior, but its treatment varies by context — the same lightning strike that excuses a common carrier may not excuse a party who had reasonable means of protection. Researchers should not assume that "act of God" analysis is uniform across contract, tort, and bailment contexts simply because lightning appears as the triggering event in all three.
For corpus researchers: lightning entries in historical legal dictionaries are thin and scattered. Bouvier's provides a physical definition drawn from Wisconsin case law; Anderson's focuses on insurance policy interpretation. Neither provides comprehensive coverage of the act of God doctrine. Researchers will need to follow cross-references to entries on Act of God, Fire, Insurance, and Vis Major to build a complete picture.
Historical Dictionary Support
Bouvier's defines lightning physically — a sudden discharge of electricity — and draws its language from Wisconsin Supreme Court authority. Bouvier's also flags the act of God classification and notes the important limitation that the act of God defense does not automatically excuse all consequences; some degree of care or preparation remains expected even against foreseeable natural hazards. This is a point frequently glossed over in secondary literature.
Anderson's takes a more applied approach, concentrating on insurance policy disputes. Its entry addresses the ignition requirement, the tornado-lightning causation problem, and (though truncated in the excerpted text) appears to extend to property descriptions involving lightning-related loss. Anderson's is more useful as a guide to litigation-tested questions; Bouvier's is more useful for foundational definitional work.
Neither dictionary addresses lightning in the context of criminal law (e.g., as a cause of death relevant to homicide or coroner's inquests), utility liability for lightning-induced equipment failures, or the modern regulatory context of lightning protection systems. These gaps reflect the state of doctrine at the time of publication rather than any principled exclusion.
Jurisdictional Note
Insurance coverage disputes over lightning damage have historically been resolved by reference to individual policy language rather than uniform statutory rules, making jurisdictional variation significant. A few states adopted standard fire policy forms by statute in the late nineteenth and early twentieth centuries, which affected how lightning was treated as a covered peril; researchers working with pre-standardization policies should not assume consistent language across jurisdictions.