Source : Webster's Revised Unabridged Dictionary (1913)

Yezdegerdian \Yez`de*ger"di*an\ (?; 277), a.
   Of or pertaining to Yezdegerd, the last Sassanian monarch of
   Persia, who was overthrown by the Mohammedans; as, the
   Yezdegerdian era, which began on the 16th of June, a. d. 632.
   The era is still used by the Parsees.