Definition of "Khorasan"

(historical) The Sassanian and post-Islamic Persian name for the region of Parthia located in north east of Persia (Iran), sometimes covering also parts of Central Asia and Afghanistan; the Greater Khorasan.

A pre-2004 province of Iran which subsequently divided into the South Khorasan, North Khorasan, and Razavi Khorasan provinces.  examples

(proscribed) Ellipsis of Daesh-Khorasan (“IS/ISIL/ISIS affiliate”).  examples