A jury is a sworn body of people (jurors) convened to hear evidence and render an impartial verdict (a finding of fact on a question) officially submitted to them by a court, or to set a penalty or judgment.
Juries developed in England during the Middle Ages and are a hallmark of the English common law system. As such, they are used by the United Kingdom, the United States, Canada, Ireland, Australia, and other countries whose legal systems were derived from the British Empire. Most other countries use variations of the European civil law or Islamic sharia law systems, in which juries are not generally used.
Most trial juries are "petit juries", and usually consist of twelve people. Historically, a larger jury known as a grand jury was used to investigate potential crimes and render indictments against suspects. All common law countries except the United States and Liberia have phased out grand juries. The modern criminal court jury arrangement has evolved out of the medieval juries in England. Members were supposed to inform themselves of crimes and then of the details of the crimes. Their function was therefore closer to that of a grand jury than that of a jury in a trial.
Etymology
The word jury derives from Latin iurare ("to swear"). Juries are most common in common law adversarial-system jurisdictions. In the modern system, juries act as triers of fact, while judges act as triers of law (but see nullification). A trial without a jury (in which both questions of fact and questions of law are decided by a judge) is known as a bench trial.
Types of jury
Petit jury
The "petit jury" (or "trial jury", sometimes "petty jury") hears the evidence in a trial as presented by both the plaintiff (petitioner) and the defendant (respondent) (also known as the complainant and defendant within the English criminal legal system). 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.
In civil cases many trials require fewer than twelve jurors.
Grand jury
A grand jury, a type of jury now confined almost exclusively to federal courts and some state jurisdictions in the United States, determines whether there is enough evidence for a criminal trial to go forward. Grand juries carry out this duty by examining evidence presented to them by a prosecutor and issuing indictments, or by investigating alleged crimes and issuing presentments. Grand juries are usually larger than trial juries: for example, U.S. federal grand juries have between 16 and 23 members. The Fifth Amendment to the U.S. Constitution guarantees Americans the constitutional right to be free from charges for "capital, or otherwise infamous" crimes unless they have been indicted by a grand jury, although this right applies only to federal law, not state law.
In addition to their primary role in screening criminal prosecutions and assisting in the investigation of crimes, grand juries in California, Florida, and some other U.S. states are sometimes utilized to perform an investigative and policy audit function similar to that filled by the Government Accountability Office in the United States federal government and legislative state auditors in many U.S. states.
Coroner's jury
A third kind of jury, known as a coroner's jury can be convened in some common law jurisdiction in connection with an inquest by a coroner. A coroner is a public official (often an elected local government official in the United States), who is charged with determining the circumstances leading to a death in ambiguous or suspicious cases, such as of Jeffrey Epstein. A coroner's jury is generally a body that a coroner can convene on an optional basis in order to increase public confidence in the coroner's finding where there might otherwise be a controversy. In practice, coroner's juries are most often convened in order to avoid the appearance of impropriety by one governmental official in the criminal justice system toward another if no charges are filed against the person causing the death, when a governmental party such as a law enforcement officer is involved in the death.