A more thorough explanation:

Definition: Standing, also known as locus standi, refers to the legal capacity of a party to bring a lawsuit in court.

In state courts, the laws of each state determine what constitutes standing. Generally, plaintiffs must have suffered or will suffer direct harm or injury, and this harm must be capable of being redressed.

In federal courts, legal actions cannot be brought simply because an individual or group is unhappy with a government action or law. Federal courts only have the constitutional authority to resolve actual disputes, known as a "case or controversy."

The Supreme Court has established a three-part test to determine whether a party has standing to sue in federal court:

1. The plaintiff must have suffered an "injury in fact," which means the injury is of a legally protected interest that is concrete and actual or imminent.
2. There must be a causal connection between the injury and the conduct brought before the court.
3. A favorable decision by the court must be likely, rather than speculative, to redress the injury.

An example of standing in state court would be a person who was injured in a car accident bringing a lawsuit against the driver who caused the accident. The plaintiff has suffered direct harm, and the harm can be redressed by the court ordering the driver to pay damages.

An example of standing in federal court would be a group of environmental activists bringing a lawsuit against a company for polluting a river. The plaintiffs must show that they have suffered a concrete and particularized injury, such as being unable to fish in the polluted river, and that the company's actions caused this harm. They must also show that a favorable decision by the court, such as ordering the company to clean up the river, is likely to redress their injury.