Oidor

Portrait of Diego del Corral y Arellano, oidor of the Council of Castile, by the painter Diego Velázquez

An oidor (Spanish pronunciation: [ojˈðoɾ]) was a judge of the Royal Audiencias and Chancillerías, originally courts of Kingdom of Castile, which became the highest organs of justice within the Spanish Empire. The term comes from the verb oír, "to hear," referring to the judge's obligation to listen to the parts of a judicial process, particularly during the phase of pleas.