Act of God describes a natural event of such magnitude that no human precaution could have prevented the resulting harm.

An affirmative defense defeats or reduces liability even if the plaintiff's allegations are true, and it must generally be pleaded in the answer or is waived.

Apportionment of fault is the jury's allocation of responsibility among the plaintiff, defendants, and in some states nonparties, expressed as percentages.

Assumption of risk bars or reduces recovery where the plaintiff voluntarily encountered a known danger.

Comparative negligence reduces a plaintiff's recovery in proportion to their own share of fault for the injury.

Contributory negligence bars recovery entirely where the plaintiff's own negligence contributed to the injury.

The empty chair defense attributes fault to a person or entity not present in the case, reducing the defendant's share of liability.

Failure to mitigate reduces damages where the plaintiff unreasonably failed to minimize the harm.

The independent contractor defense denies vicarious liability for the acts of a contractor rather than an employee.

An intervening cause is an event occurring after the defendant's conduct that contributes to the harm.

Modified comparative fault reduces recovery by the plaintiff's share of fault but bars it above a defined threshold.

Nonparty fault allocation permits a jury to assign responsibility to persons who are not parties to the action.

The seat belt defense argues that a plaintiff's failure to use a seat belt increased the injuries sustained.

The sudden emergency doctrine holds that a person facing an unexpected peril is judged by what is reasonable under emergency conditions.

A superseding cause is an intervening event that breaks the causal chain and relieves the original actor of liability.

Unavoidable accident describes an event occurring without negligence by any party, defeating a negligence claim.