Plaintiff in the context of "Form of action"

In law, standing or locus standi is a condition that a party seeking a legal remedy must show they have, by demonstrating to the court, sufficient connection to and harm from the law or action challenged to support that party's participation in the case. A party has standing in the following situations:

• The party is directly subject to an adverse effect by the statute or action in question, and the harm suffered will continue unless the court grants relief in the form of damages or a finding that the law either does not apply to the party or that the law is void or can be nullified. In informal terms, a party must have something to lose. The party has standing because they will be directly harmed by the conditions for which they are asking the court for relief.
• The party is not directly harmed by the conditions for which they are petitioning the court for relief but asks for it because the harm involved has some reasonable relation to their situation, and the continued existence of the harm may affect others who might not be able to ask a court for relief. In the United States, this is grounds for asking for a law to be struck down for violating the First Amendment to the Constitution of the United States, because, even though the plaintiff might not be directly affected, the law might adversely affect others, because they might not know when they were violating it. This is known as the "chilling effects" doctrine.
• The party is granted automatic standing by act of law. For example, under some environmental laws in the United States, a party may sue someone causing pollution to certain waterways without a federal permit, even if the party suing is not harmed by the pollution being generated. The law allows the plaintiff to receive attorney's fees from the defendant if they substantially prevail in the action. In some U.S. states, a person who believes a book, film, or other work of art is obscene may sue in their own name to have the work banned directly without having to ask a district attorney to do so.

In the United States, a person may not bring a suit challenging the constitutionality of a law unless they can demonstrate that they are or will "imminently" be harmed by the law. Otherwise, the court will rule that the plaintiff lacks standing to bring the suit and will dismiss it without considering the merits of the claim of unconstitutionality.

In common law, a petit jury (or trial jury; pronounced /ˈpɛtət/ or /pəˈtiːt/, depending on the jurisdiction) hears the evidence in a trial as presented by both the plaintiff (petitioner) and the defendant (respondent). After hearing the evidence and often jury instructions from the judge, the group retires for deliberation, to consider a verdict. The majority required for a verdict varies. In some cases it must be unanimous, while in other jurisdictions it may be a majority or supermajority. A jury that is unable to come to a verdict is referred to as a hung jury. The size of the jury varies; in criminal cases involving serious felonies there are usually 12 jurors, although Scotland uses 15. A number of countries that are not in the English common law tradition have quasi-juries on which lay judges or jurors and professional judges deliberate together regarding criminal cases. However, the common law trial jury is the most common type of jury system.

In civil cases many trials require fewer than twelve jurors. Juries are almost never used in civil cases outside the United States and Canada. Other states with a common law tradition sometimes use them in defamation cases, in cases involving a governmental eminent domain power, and in cases involving alleged wrongful conviction. Civil law countries generally do not use civil juries. Civil juries are available in the United States and Canada in almost all cases where the only remedy sought is money damages.

In law, liable means "responsible or answerable in law; legally obligated". Legal liability concerns both civil law and criminal law and can arise from various areas of law, such as contracts, torts, taxes, or fines given by government agencies. The claimant is the one who seeks to establish, or prove, liability.

A lawsuit is a proceeding by one or more parties (the plaintiff or claimant) against one or more parties (the defendant) in a civil court of law. The archaic term "suit in law" is found in only a small number of laws still in effect today. The term "lawsuit" is used with respect to a civil action brought by a plaintiff (a party who claims to have incurred loss as a result of a defendant's actions) who requests a legal remedy or equitable remedy from a court. The defendant is required to respond to the plaintiff's complaint or else risk default judgment. If the plaintiff is successful, judgment is entered in favor of the plaintiff, and the court may impose the legal or equitable remedies available against the defendant (respondent). A variety of court orders may be issued in connection with or as part of the judgment to enforce a right, award damages or restitution, or impose a temporary or permanent injunction to prevent an act or compel an act. A declaratory judgment may be issued to prevent future legal disputes.

A lawsuit may involve resolution of disputes involving issues of private law between individuals, business entities or non-profit organizations. A lawsuit may also involve issues of public law in the sense that the state is treated as if it were a private party in a civil case, either as a plaintiff with a civil cause of action to enforce certain laws or as a defendant in actions contesting the legality of the state's laws or seeking monetary damages for injuries caused by agents of the state.

In law, a witness is someone who, either voluntarily or under compulsion, provides testimonial evidence, either oral or written, of what they know or claim to know.

A witness might be compelled to provide testimony in court, before a grand jury, before an administrative tribunal, before a deposition officer, or in a variety of other legal proceedings. A subpoena is a legal document that commands a person to appear at a proceeding. It is used to compel the testimony of a witness in a trial. Usually, it can be issued by a judge or by the lawyer representing the plaintiff or the defendant in a civil trial or by the prosecutor or the defense attorney in a criminal proceeding, or by a government agency. In many jurisdictions, it is compulsory to comply with the subpoena and either take an oath or solemnly affirm to testify truthfully under penalty of perjury.

An inquisitorial system is a legal system in which the court, or a part of the court, is actively involved in investigating the facts of the case. This is distinct from an adversarial system, in which the role of the court is primarily that of an impartial referee between the plaintiff or prosecution and the defense.

Inquisitorial systems are used primarily in countries with civil legal systems, such as France and Italy, or legal systems based on Islamic law like Saudi Arabia, rather than in common law systems. It is the prevalent legal system in Continental Europe, Latin America, African countries not formerly under British rule, East Asia (except Hong Kong), Indochina, Thailand, and Indonesia. Most countries with an inquisitorial system also have some form of civil code as their main source of law. Countries using common law, including the United States, may use an inquisitorial system for summary hearings in the case of misdemeanors or infractions, such as minor traffic violations.

In legal terminology, a complaint is any formal legal document that sets out the facts and legal reasons (see: cause of action) that the filing party or parties (the plaintiff(s)) believes are sufficient to support a claim against the party or parties against whom the claim is brought (the defendant(s)) that entitles the plaintiff(s) to a remedy (either money damages or injunctive relief). For example, the Federal Rules of Civil Procedure (FRCP) that govern civil litigation in United States courts provide that a civil action is commenced with the filing or service of a pleading called a complaint. Civil court rules in states that have incorporated the Federal Rules of Civil Procedure use the same term for the same pleading.

In Civil Law, a "complaint" is the first formal action taken to officially begin a lawsuit. This written document contains the allegations against the defense, the specific laws violated, the facts that led to the dispute, and any demands made by the plaintiff to restore justice.