Emir, a title bestowed on the descendants of Mahomet's daughter Fatima, the word denoting a “prince” or “ruler”; has lost this its primary meaning; the emirs, of whom there are large numbers in Turkey, enjoying no privileges save the sole right to wear a green turban, the supposed favourite colour of Mahomet, though they hold a high social position; the title is also given to chieftains of N. Africa.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Émile * Emmet, Robert