Persons appointed by competent authority to draw up official or authentic documents which are issued from chanceries or tribunals.
As soon as a bureau for ecclesiastical documents was established, we find evidence of notaries, and in the time of Pope Julius I (4th century) the notaries formed a kind of college presided over by a "primicerius" or chief.
At present the only ecclesiastical notaries are the officials of the episcopal and Roman curiae, who also act as secretaries, and those who are appointed to the ordinary tribunals of the Holy See, the Rota, and the Signatura.
They are similar to registrars and clerks of the court in civil trials, and are usually clerics.
New Catholic Dictionary