Defendant
A defendant is a person or entity accused of a crime in criminal prosecution or a person or entity against whom some type of civil relief is being sought in a civil case.
Terminology varies from one jurisdiction to another. For example, Scots law does not use the term "defendant"; the terms "accused" or "panel" are used instead in criminal proceedings, and "defender" in civil proceedings.
Criminal defendants
In a criminal trial, a defendant is any person accused (charged) of committing an offense (a crime; an act defined as punishable under criminal law). The other party to a criminal trial is usually a public prosecutor, but in some jurisdictions, private prosecutions are allowed.
Criminal defendants are often taken into custody by police and brought before a court under an arrest warrant. Criminal defendants are usually obliged to post bail before being released from custody. For serious cases, such as murder, bail is often refused. Defendants must be present at every stage of the proceedings against them. (There is an exception for very minor cases such as traffic offenses in jurisdictions which treat them as crimes.)