Magistrate

A magistrate is a law officer who administers the law in a court. The term varies in its use in different countries.
Early years.
In ancient Rome, a "magistratus" was one of the highest ranking government officers. They had judicial and executive powers. 
Recent examples.
In some parts of the world, such as China, a magistrate was responsible for administration over a particular geographic area. Today, in some jurisdictions, a magistrate is a judicial officer who hears cases in a lower court. They usually deal with minor or preliminary matters. In England and Wales there are two types of magistrates: justices of the peace and district judges.