الاشتيام

, with kesr, [which seems to indicate that it is الإِشْتِيَامُ,] is explained by IB as meaning ريءيس الركاب [apparently رَيءِيسُ الرُّكَّابِ The headman, or master, of the riders: but whence this is derived I know not, unless it be arabicized, from the Pers. أُسْتَا يَام (if there be such an appellation), meaning “ the master of the post-horse ”]. (TA.)