Tort is the French word for a "wrong." A tort is a non-contractual, non-criminal wrongdoing.

This definition with two words using 'non' captures the fact that tort law is a remainder category, a grab bag of legal cases comprising such disparate topics as auto accidents, false imprisonment, slander and libel, product liability (such as defectively designed consumer products), and environmental pollution (toxic torts).

Tort law, in common legal parlance, is a body of law that deals with civil wrongdoings. The definition of this kind of wrong is usually distinct from a criminal wrong. A person who suffers legal damage may be able to use tort law to receive damages (usually monetary compensation) from someone who is responsible or liable for those injuries. Generally speaking, tort law defines what is a legal injury and what is not. A person may be held liable (responsible to pay) for another's injury caused by them. The major categories of torts are intentional torts, negligent torts, and strict liability torts.

For example, Alice throws a ball and accidentally hits Brenda in the eye. Brenda may sue Alice for losses occasioned by the accident (such as the cost of medical treatment and lost pay due to missing work), as well as for punitive damages. Whether or not Brenda wins her lawsuit depends on whether she can prove Alice engaged in tortious conduct. Here, Brenda would try to prove that Alice had a responsibility not to harm people and failed to exercise the responsibility which a reasonable person would render in throwing the ball. This is an example of the negligence tort.

One of the main topics of the substance of tort law is determining the standard of care—a legal phrase that means deciding between when conduct is or is not wrong or illegal. Put another way, the main issue is whether a person must cope with the loss suffered on his or her own, or whether the loss will be compensated (paid for) by another party.

In much of the Western world, the measure of tort liability is negligence. If the injured party cannot prove that the person believed to have caused the injury acted with negligence (lack of reasonable care), at the very least, tort law will not compensate (pay) the victim. However, tort law also recognizes intentional (purposeful) torts and strict liability torts, which apply when the person accused of committing the tort satisfied certain standards of intent (meaning) and/or performed certain types of conduct.

In tort law, injury is defined broadly. Injury does not just mean a physical injury, such as where Brenda was struck by a ball. Injuries in tort law reflect any invasion of any number of individual interests. This includes interests recognized in other areas of law, such as property rights. Actions for nuisance (annoying or hurting) and trespass (unlawful entering) of land can arise from interfering with rights in real property. Conversion law and trespass to chattels (personal property) can protect interference with movable property. Interests in prospective (possible future) economic advantages from signed agreements can also be injured and become the subject of tort actions. A number of situations caused by parties in a contractual (written agreement) relationship may still be tort rather than contract claims, such as breach of duties.

Tort law may also be used to compensate (pay) for injuries to a number of other individual interests that are not recognized in property or contract law. This includes an interest in freedom from emotional distress, privacy interests, and reputation. These are protected by a number of torts such as Intentional infliction of emotional distress, privacy torts, and defamation/slander (destruction of a reputation). Defamation and privacy torts may, for example, allow a celebrity to sue a newspaper for publishing an untrue and harmful statement about him. Other protected interests include freedom of movement, protected by the intentional tort of false imprisonment which is when you are arrested without cause.

The equivalent of tort in civil law jurisdictions is delict. The law of torts can be categorised as part of the law of obligations (duties), but unlike voluntarily assumed obligations (such as those of contract, or trust), the duties imposed by the law of torts apply to all those subject to the relevant jurisdiction. To behave in tortious manner is to harm another's rights, body, property or other rights. One who commits a tortious act is called a tortfeasor.