Informed Comment

DIRRAH درة
Vulg. durrah. A scourge made either of a flat piece of leather or of twisted thongs, and used by the public censor of morals and religion, called the muhtasib. This scourge is inflicted wither for the omission of the daily prayer, or for the committal of sins, which are punishable by the law with the infliction of stripes, such as fornication, scandal, and drunkenness. It is related that the Khalifah ‘Umar punished his son with the durrah for drunkenness, and that he died from its effects. (Tarikh-I-Khamis, vol ii, p 252.)
The word used in the Qur’an and Hadis for this scourge is jaldah, and in theological works, saut; but dirrah is now the word generally used amongst modern Muslims.

Based on Hughes, Dictionary of Islam