Roman Rota
The Sacra Rota Romana or Sacred Roman Rota is the supreme court of the Roman Catholic Church.
It is named Rota (wheel) because of the court's judges rotate between cases: while twelve judges hear a case, there are more than 12 members of the Rota. They are assigned to each case like a queue ; for each new case, one judge is taken off one end of the queue, another one is added at the other end.
The Rota's main function is that of an appelate court, hearing appeals from each diocese's courts. Nowadays it mainly hears marriage annulment cases due to the increased divorce rates, including among Catholics, but it can hear cases in any area of Canon Law. The Rota's decision can further be appealled to the Pope himself, whose decision is irreversible, but this is very rarely done.
The Rota's other function is that of clarification. Any Catholic can ask the Rota to clarify and give a definitive interpretation of Canon Law. Like all supreme courts, the Rota may (and does) later change its interpretation of the texts it is tasked to enforce.