Source : Webster's Revised Unabridged Dictionary (1913)

Hyksos \Hyk"sos\, n. [Gr. ?, fr. Egypt. hikshasu chiefs of the
   Bedouins, shepherds.]
   A dynasty of Egyptian kings, often called the {Shepherd
   kings}, of foreign origin, who, according to the narrative of
   Manetho, ruled for about 500 years, forming the XVth and
   XVIth dynasties. It is now considered that the XVIth is
   merely a double of the XVth dynasty, and that the total
   period of the six Hyksos kings was little more than 100
   years. It is supposed that they were Asiatic Semites.