Русско-англо-русский юридический словарь

More than half of the states and all of the federal circuits permit jurors to submit written questions for witnesses but leave it to the discretion of the trial judge to decide whether to permit the practice in any given case. (gov.scot)

Historically, in the U.S., state and federal court trial judges, for example, had to travel routinely to numerous locations in a specific geographical region to hear cases. People referred to the various locations with the region as a circuit; this is how the term circuit judge came about. Today a circuit judge is more likely to be assigned to just one courthouse. (PracticalAdultInsights)