One of the Earliest Classical Arabic Dictionaries Known:

KITAB AL-AYN كتاب العين - Khalil ibn Ahmad al-Farhidi [d. 174/791]

Source 1  http://www.aboutquran.com/res/lex/Lexicon.htm

[Direct Link to the above site for source. References from the above site for description]

"The dictionary was not arranged alphabetically but rather by phonetics, following the pattern of pronunciation of the Arabic alphabet from the deepest letter of the throat ﻉ (ayn) to the last letter pronounced by the lips, that being م (mìm)"

Source 2  http://www.archive.org/details/alaeen_Farahidi