IRAN, the great plateau between the plain of the Tigris in the west and the valley of the Indus in the east, the Caspian Sea and the Turanian desert in the north, and the Persian Gulf and the Indian Ocean in the south, surrounded on all sides by high mountain ranges with a great salt desert in the centre. The mod em name Iran (in middle-Persian, Eran) is derived from the an cient Aryana, "the country of the Aryans." Eratosthenes limited the name of Ariana to the south-eastern part of Iran, and excluded Persia, Media and Bactria, and therein he is followed by Strabo (ii. 78, 13o, xv. 72o ff.; Pomp. Mela i. 3.)
The term Iran, having always been used by native Persians to designate their indefinitely bounded country, became current in western usage after 1927 as the name of the kingdom proper in recognition of its reinvigorated life and newly asserted inde pendence.
For the ethnography and history of Iran see PERSIA.