A vow of silence or oath of silence was an oath made by an individual to not speak at all, or only to a limited number of people. The vow could be personal or religious in nature. In 2369 after a Hunter found a Tosk in a holding cell aboard Deep Space 9 he asked him how he managed to get the help of these aliens without violating his oath of silence. (DS9: "Captive Pursuit") Hupyrian servants took partial vows of silence which forbade them from speaking to anyone other than to their Ferengi masters. (DS9: "Prophet Motive")