SARACEN. A term used by Christian writers for the followers of Muhammad, and applied not only to the Arabs, but to the Turks and other Muslim nations.
There is much uncertainty as to the origin of this word. The word was used by Ptolemy and Pliny, and also by Ammianus and Precopius, for certain Oriental tribes, long before the death of Muhammad (see Gibbon). Some etymologists derive it from the Arabic sharq,” the rising sun, the East” (see Wedgwood’s Diet). Others from sahra’ “a desert,”— the people of the desert (see Webster). Gibbon thinks it may be from the Arabic saraqah, “theft,” denoting the thievish character of the nation; whilst some have even thought it may be derived from Sarah the wife of the Patriarch Abraham.
Based on Hughes, Dictionary of Islam