S. al-Theeb reads dmy for dsy here as well as ThNIS 7 and 20, in this group of inscriptions, but in ThNIS 16, it is clear that the second letter is a s.
al-Theeb, Solaiman Abdal-Rahman 2011. New Nabataean inscriptions from the site of al-Sīj in the region of al-‘Ulā, Saudi Arabia. Proceedings of the Seminar for Arabian Studies, 41: 349-370.