A more thorough explanation:

Definition: Judex (joo-deks) is a Latin term that has multiple meanings:

1. In Roman law, a private person appointed by a praetor or other magistrate to hear and decide a case. Originally, the Roman judex was selected from a panel of qualified persons of standing, but later became a magistrate himself.
2. In Roman and civil law, a judge.
3. In history, a juror.

There are also specific types of judex:

• Judex ad quem: A judge to whom an appeal is taken in civil law.
• Judex a quo: A judge from whom an appeal is taken in civil law.
• Judex datus: A judex assigned by a magistrate or provincial governor to try a case under cognitio extraordinaria.
• Judex delegatus: A delegated judge under cognitio extraordinaria; a special judge.
• Judex fiscalis: A judex having jurisdiction of matters relating to the fiscus.
• Judex ordinarius: A judge having jurisdiction in his own right rather than by delegated authority.
• Judex pedaneus: A judex to whom petty cases are delegated; an inferior or deputy judge under cognitio extraordinaria.
• Judex quaestionis: The chairman of the jury in a criminal case, either a praetor or a magistrate of lower rank.
• Judex selectus: A judge selected to hear the facts in a criminal case.
• Judex specialis: A judex who is an inferior or deputy judge under cognitio extraordinaria.

For example, a judex ad quem is a judge to whom an appeal is taken in civil law. If a person is unhappy with the decision made by a lower court, they can appeal to a higher court and have their case heard by a judex ad quem. Similarly, a judex specialis is a type of judex who is an inferior or deputy judge under cognitio extraordinaria. This means that they are appointed to hear specific types of cases, such as petty cases in the case of a judex pedaneus.