The Joint Senate of the Federal Supreme Courts of Justice (Gemeinsamer Senat der Obersten Gerichtshöfe des Bundes, also called the Common Senate) is often regarded as one of the supreme courts of justice in Germany, but it is rather, as the name suggests, an ad-hoc judicial body, that is convened in specific cases only. The Joint Senate consists of the Presidents of the five Federal Supreme Courts (excluding the Bundesverfassungsgericht) and two members of each of the senates involved ("Senate" denotes a judicial 'sub-unit' within a court, usually consisting of three or more judges. All Federal Supreme Courts, as well as subordinate courts of appeal, are divided into several senates). The Joint Senate decides on questions regarding the interpretation of law that are relevant for all five branches of law overseen by the five Federal Supreme Courts.
The Joint Senate gathers rarely (between 2000 and 2010, there were only three decisions), as the areas of responsibility of the branches of justice in Germany are in general well-defined, so its rulings are mostly on definitory matters. Its meetings are organised by the Bundesgerichtshof in Karlsruhe.
The Joint Senate should not be confused with the Great Senate that exists within each Federal Supreme Court. Its function is similar to that of the Joint Senate, as it mediates between the several senates of a Supreme Court in cases of dissent. To make things even more confusing, the Bundesgerichtshof has not one Great Senate, but three: one for civil law issues, one for criminal law issues, and one for disputes between the criminal law senates and the civil law senates. Also, the Bundesverfassungsgericht has a similar body, which in this case is called the Plenum, which consists of all the judges of the court and which gathers, again, only if a dispute arises between two different senates which cannot be resolved otherwise. This case has only occurred five times, with the most recent such decision being from 2012.