in the United States
A lawsuit or (very rarely) "suit in law" is a civil action brought in a court of law in which a plaintiff, a party who claims to have incurred loss as a result of a defendant's actions, demands a legal or equitable remedy. The defendant is required to respond to the plaintiff's complaint. If the plaintiff is successful, judgment is in the plaintiff's favor, and a variety of court orders may be issued to enforce a right, award damages, 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 dispute resolution of private law issues between individuals, business entities or non-profit organizations. A lawsuit may also enable the state to be treated as if it were a private party in a civil case, as plaintiff, or defendant regarding an injury, or may provide the state with a civil cause of action to enforce certain laws.
The conduct of a lawsuit is called litigation. One who has a tendency to litigate rather than seek non-judicial remedies is called litigious. The plaintiffs and defendants are called litigants and the attorneys representing them are called litigators.
The term litigation may also refer to criminal trial.
Rules of procedure and complications 
Rules of criminal or civil procedure govern the conduct of a lawsuit in the common law adversarial system of dispute resolution. Procedural rules are additionally constrained/informed by separate statutory laws, case law, and constitutional provisions that define the rights of the parties to a lawsuit (see especially due process), though the rules generally reflect this legal context on their face. The details of procedure differ greatly from jurisdiction to jurisdiction, and often from court to court within the same jurisdiction. The rules are very important for litigants to know, however, because they dictate the timing and progression of the lawsuit—what may be filed and when, to obtain what result. Failure to comply with the procedural rules may result in serious limitations upon the ability to present claims or defenses at any subsequent trial, or even dismissal of the lawsuit.
Though the majority of lawsuits are settled and never reach trial, they can be very complicated to litigate. This is particularly true in federal systems, where a federal court may be applying state law (e.g., the Erie doctrine in the United States) or vice versa, or one state applying the law of another, and where additionally may not be clear which level (or location) of court actually has jurisdiction over the claim or personal jurisdiction over the defendant, or whether the plaintiff has standing to participate in a lawsuit. About 98 percent of civil cases in the United States federal courts are resolved without a trial. Domestic courts are also often called upon to apply foreign law, or to act upon foreign defendants, over whom they may not, as a practical matter, even have the ability to enforce a judgment if the defendant's assets are outside their reach.
Lawsuits become additionally complicated as more parties become involved (see joinder). Within a "single" lawsuit, there can be any number of claims and defenses (all based on numerous laws) between any number of plaintiffs or defendants, each of whom can bring any number of cross-claims and counterclaims against each other, and even bring additional parties into the suit on either side after it progresses. However, courts typically have some power to sever claims and parties into separate actions if it is more efficient to do so, such as if there is not a sufficient overlap of factual issues between the various associates.
The following is a generalized description of how a lawsuit may proceed in a common law jurisdiction:
A lawsuit begins when a complaint is filed with the court. This complaint states that one or more plaintiffs seeks damages or equitable relief from one or more stated defendants, and identifies the legal and factual bases for doing so. It is important that the "plaintiff selects the proper venue with the proper jurisdiction to bring his lawsuit." The clerk of a court signs or stamps the court seal upon a summons, which is then served by the plaintiff upon the defendant, together with a copy of the complaint. This service notifies the defendants that they are being sued and that they have a specific time limit to file a response. By providing a copy of the complaint, the service also notifies the defendants of the nature of the claims. Once the defendants are served with the summons and complaint, they are subject to a time limit to file an answer stating their defenses to the plaintiff's claims, including any challenges to the court's jurisdiction, and any counterclaims they wish to assert against the plaintiff.
In a handful of jurisdictions (notably, the U.S. state of New York) a lawsuit begins when one or more plaintiffs properly serve a summons and complaint upon the defendant(s). In such jurisdictions, nothing must be filed with the court until a dispute develops requiring actual judicial intervention.
If the defendant chooses to file an answer within the time permitted, the answer must address each of the plaintiffs' allegations by admitting the allegation, denying it, or pleading a lack of sufficient information to admit or deny the allegation. Some jurisdictions, like California, still authorize general denials of each and every allegation in the complaint. At the time the defendant files an answer, the defendant also raises all "affirmative" defenses. The defendant may also assert counterclaims for damages or equitable relief against the plaintiff, and in the case of "compulsory counterclaims," must do so or risk having the counterclaim barred in any subsequent proceeding. The defendant may also file a "third party complaint" seeking to join another party or parties in the action in the belief that those parties may be liable for some or all of the plaintiff's claimed damages. Filing an answer "joins the cause" and moves the case into the pre-trial phase.
Instead of filing an answer within the time specified in the summons, the defendant can choose to dispute the validity of the complaint by filing a demurrer (in the handful of jurisdictions where that is still allowed) or one or more "pre-answer motions," such as a motion to dismiss. The motion must be filed within the time period specified in the summons for an answer. If all such motions are denied by the trial court, and the defendant loses on all appeals from such denials (if that option is available), then the defendant must file an answer.
Usually the pleadings are drafted by a lawyer, but in many courts persons can file papers and represent themselves, which is called appearing pro se. Many courts have a pro se clerk to assist people without lawyers.
Pretrial discovery 
The early stages of the lawsuit may involve initial disclosures of evidence by each party and discovery, which is the structured exchange of evidence and statements between the parties. Discovery is meant to eliminate surprises and clarify what the lawsuit is about, and to make the parties realize they should settle or drop frivolous claims and defenses. At this point the parties may also engage in pretrial motions to exclude or include particular legal or factual issues before trial.
At the close of discovery, the parties may either pick a jury and then have a trial by jury or the case may proceed as a bench trial heard only by the judge if the parties waive a jury trial or if the right to a jury trial is not guaranteed for their particular claim (such as those under equity in the U.S.) or for any lawsuits within their jurisdiction.
Trial and judgment 
At trial, each person presents witnesses and enters evidence into the record, at the close of which the judge or jury renders their decision. Generally speaking, the plaintiff has the burden of proof in making his claims. The defendant may have the burden of proof on other issues, however, such as affirmative defenses. The attorneys will devise a trial strategy that ensures they meet the necessary elements of their case or (when the opposing party has the burden of proof) to ensure the opponent will not be able to meet his or her burden.
There are numerous motions that either party can file throughout the lawsuit to terminate it "prematurely"—before submission to the judge or jury for final consideration. These motions attempt to persuade the judge, through legal argument and sometimes accompanying evidence, that because there is no reasonable way that the other party could legally win, there is no sense in continuing with the trial. Motions for summary judgment, for example, can usually be brought before, after, or during the actual presentation of the case. Motions can also be brought after the close of a trial to undo a jury verdict contrary to law or against the weight of the evidence, or to convince the judge to change the decision or grant a new trial.
Also, at any time during this process from the filing of the complaint to the final judgment, the plaintiff may withdraw the complaint and end the whole matter, or the defendant may agree to a settlement. If the case settles, the parties might choose to enter into a stipulated judgment with the settlement agreement attached, or the plaintiff may simply file a voluntary dismissal, so that the settlement agreement is never entered into the court record.
After a final decision has been made, either party or both may appeal from the judgment if they believe there had been a procedural error made by the trial court. Even the prevailing party may appeal, if, for example, they wanted a larger award than was granted. The appellate court (which may be structured as an intermediate appellate court) and/or a higher court then affirms the judgment, declines to hear it (which effectively affirms it), reverses—or vacates and remands, which involves sending the lawsuit back to the lower trial court to address an unresolved issue, or possibly for a whole new trial. Some lawsuits go up and down the appeals ladder repeatedly before finally resolution.
Some jurisdictions, notably the United States, prevent parties from relitigating the facts on appeal, due to a history of unscrupulous lawyers deliberately reserving such issues in order to ambush each other in the appellate courts (the "invited error" problem). The idea is that it is more efficient to force all parties to fully litigate all relevant issues of fact before the trial court. Thus, a party who does not raise an issue of fact at the trial court level generally cannot raise it on appeal. Furthermore, appellate courts in such jurisdictions will not question the facts as found by a judge or jury in the trial court, as long as there was some evidence in the record to support such findings—and even if the appellate judge would not personally have believed the underlying evidence if present when it was entered into the record.
When the lawsuit is finally resolved, or the allotted time to appeal has expired, the matter is res judicata. The plaintiff may not bring another action based on the same claim again. In addition, other parties who later attempt to re-litigate a matter already ruled on in a previous lawsuit will be estopped from doing so.
When a final judgment is entered, the plaintiff is usually barred under the doctrine of res judicata from trying to bring the same or similar claim again against that defendant, or from relitigating any of the issues, even under different legal claims or theories. This prevents a new trial of the same case with a different result, or if the plaintiff won, a repeat trial that merely multiplies the judgment against the defendant.
If the judgment is for the plaintiff, then the defendant must comply under penalty of law with the judgment, which is usually a monetary award. If the defendant fails to pay, the court has various powers to seize any of the defendant's assets located within its jurisdiction, such as:
If all assets are located elsewhere, the plaintiff must file another suit in the appropriate court to seek enforcement of the other court's previous judgment. This can be a difficult task when crossing from a court in one state or nation to another, though courts tend to grant each other respect when there is not a clear legal rule to the contrary. A defendant who has no assets in any jurisdiction is said to be "judgment-proof." The term is generally a colloquialism to describe an impecunious defendant.
Indigent judgment-proof defendants are no longer imprisoned; debtor's prisons have been outlawed by statute, constitutional amendment, or international human rights treaties in the vast majority of common law jurisdictions.
During the 18th and 19th centuries, it was common for lawyers to speak of bringing an "action" at law and a "suit" in equity. An example of that distinction survives today in the text of the Civil Rights Act of 1871. The fusion of common law and equity in England in the Judicature Acts of 1873 and 1875 led to the collapse of that distinction, so it became possible to speak of a "lawsuit." In the United States, the Federal Rules of Civil Procedure (1938) abolished the distinction between actions at law and suits in equity in federal practice, in favor of a single form referred to as a "civil action."
American terminology is slightly different, in that the term "claim" refers only to a particular count (or cause of action) in a lawsuit. Americans also use "claim" to describe a demand filed with an insurer or administrative agency. If the claim is denied, then the claimant (or policyholder or applicant) files a lawsuit with the courts and becomes a plaintiff.
In medieval times, both "action" and "suit" had the approximate meaning of some kind of legal proceeding, but an action terminated when a judgment was rendered, while a suit also included the execution of the judgment.
In the United States, plaintiffs and defendants who lack financial resources for litigation or other legal expenses may be able to obtain legal financing. Legal financing companies can provide a cash advance to litigants in return for a share of the ultimate settlement or award. If the case ultimately loses, the litigant does not have to pay any of the money funded back. Legal financing is different from a typical bank loan. The legal financing company does not look at credit history or employment history. Litigants do not have to repay the cash advance with monthly payments, but do have to fill out an application so that the legal financing company can review the merits of the case.
Legal financing can be a practical means for litigants to obtain financing while they wait for a monetary settlement or an award in their personal injury, workers' compensation, or civil rights lawsuit. Often, plaintiffs who were injured or forced to leave their jobs still have mortgages, rent, medical expenses, or other bills to pay. Other times, litigants may simply need money to pay for the costs of litigation and attorneys' fees. For this reason, many litigants turn to reputable legal financing companies to apply for a cash advance to help pay for bills.
Defendants, civil rights organizations, public interest organizations, and government public officials can set up an account to pay for litigation costs and legal expenses. These legal defense funds can have large membership counts where the members contribute to the fund. Unlike legal financing from legal financing companies, legal defense funds provide a separate account for litigation rather than a one-time cash advancement, though both are used for purposes of financing litigation and legal costs.
See also 
|Look up lawsuit or actio popularis in Wiktionary, the free dictionary.|
- Actio popularis
- compensation culture
- divorce lawsuit
- frivolous litigation
- legal defense fund
- legal financing
- list of environmental lawsuits
- personal injury
- restorative justice
- The archaic term "suit in law" is found in only a small number of laws still in effect today, such as the Eleventh Amendment to the United States Constitution.
- Definition of 'litigious' at Answers.com
- Abrams, Lisa L. (2000) "Civil Litigation The Official Guide to Legal Specialties National Association for Law Placement, Harcourt Legal & Professional Publications, Chicago, page 71, ISBN 978-0-15-900391-6
- The Lawsuit Survival Guide by Joseph L. Matthews ?. ISBN 0-87337-760-5
- "?". Retrieved 20 August 2010.
- Dionne, Georges (1992). Foundations of Insurance Economics: Readings in Economics and Finance. Springer. ISBN 0-7923-9204-3.