KHALIL IBN AHMAD, AL-

born c. 718, , Oman died , between 776 and 791, Basra, Iraq in full Al-khalil Ibn Ahmad Ibn 'amr Ibn Tamim Al-farahidi Al-azdi Al-yuhmadi Al-basri Abu 'abd Al-rahman Arab philologist who compiled the first Arabic dictionary and is credited with the formulation of the rules of Arabic prosody. When he moved to Basra, al-Khalil left the Ibadi sect of Islam, which was popular in his native Oman, for Sunnism (the largest branch of Islam). He lived simply and piously in Basra, where he taught. The renowned Sibawayh was among his students. His dictionary, Kitab al-'ayn (Book of the 'Ayn), may have been written in part by his student al-Layth ibn al-Muzaffar of Khorasan, who was at one time secretary to the Barmakid viziers of the 'Abbasid court. It is arranged according to a novel alphabetical order based on pronunciation, beginning with the letter 'ayn. His sample verses from his work on poetry, Kitab al-'arud (Book of Prosody), are known, although his book is lost.