Official nameJomhuri-e-Eslami-e-Iran (Islamic Republic of Iran)CapitalTehranPopulation estimate (2015)79·11 millionInternet domain extension.irCurrencyThe unit of currency is the rial (IRR).TerritoryIran is bounded in the north by Armenia, Azerbaijan, the Caspian Sea and Turkmenistan, east by Afghanistan and Pakistan, south by the Gulf of Oman and the Persian Gulf, and west by Iraq and Turkey.LanguageThe official language is Farsi or Persian.Source: The Statesman's Yearbook 2018. Palgrave Macmillan, London Synonyms and related words