A tribunal, generally, is any person or institution with authority to judge, adjudicate on, or determine claims or disputes—whether or not it is called a tribunal in its title.
For example, an advocate who appears before a court with a single judge could describe that judge as "their tribunal." Many governmental bodies that are titled as "tribunals" are described so in order to emphasize that they are not courts of normal jurisdiction. For example, the International Criminal Tribunal for Rwanda was a body specially constituted under international law; in Great Britain, employment tribunals are bodies set up to hear specific employment disputes. In many (but not all) cases, the word tribunal implies a judicial (or quasi-judicial) body with a lesser degree of formality than a court, in which the normal rules of evidence and procedure may not apply, and whose presiding officers are frequently neither judges, nor magistrates. Private judicial bodies are also often styled "tribunals." The word tribunal, however, is not conclusive of a body's function—for example, in Great Britain, the Employment Appeal Tribunal is a superior court of record.
The term is derived from the tribunes, magistrates of the Classical Roman Republic. "Tribunal" originally referred to the office of the tribunes, and the term is still sometimes used in this sense in historical writings. The tribunal was the platform upon which the presiding authority sat; having a raised position physically as symbolic of his higher position in regard to the adjudication of the law.
In Australia, the term tribunal generally implies a judicial body with a lesser degree of formality than a court, with a simplified legal procedure, often presided over by a lawyer (solicitor or barrister) who is not a judge or magistrate (often referred to as a member of the tribunal). In many cases the lawyers who function as tribunal members do so only on a part-time basis, and spend the greater part of their time carrying out other aspects of legal practice, such as representing clients.