Al-dhira al-mirathiyah
Definition of "Al-dhira al-mirathiyah"
A cubit devised by the ‘Abbasid caliph al- Mamun al-Rashid (AD 813–833) to measure barid (post stages), embankments, suqs, canals and excavations; equal to one dhira‘ al-Sawad plus two-thirds of the same plus two-thirds of a finger.