Source : Webster's Revised Unabridged Dictionary (1913)

Usbegs \Us"begs\, Usbeks \Us"beks\, n. pl. (Ethnol.)
   A Turkish tribe which about the close of the 15th century
   conquered, and settled in, that part of Asia now called
   Turkestan. [Written also {Uzbecks}, and {Uzbeks}.]