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 modern name Iran, in middle-Persian Eran (a form preferred by many German authors) is derived from the ancient Aryana, " the country of the Aryans," i.e. that part of the Aryans which we call Iranians. 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, 130, xv. 720 ff.; Pomp. Mela i. 3; Pliny, Nat. Hist. vi. 113, 116, xii. 33); Pliny (Nat. Hist. vi. 93) confounds it with Aria, Areia, Pers. Haraiva, i.e. the district of Herat; but Strabo himself says (xv. 724) that some extended the name to the Persians, Medes, Bactrians and Sogdians, as they all spoke the same language with small dialectic variations (cf. 727 and i. 66, xi. 523).
For the ethnography and history of Iran see PERSIA. (Eo. M.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)