The Collaborative International Dictionary of English v.0.48:

Chickasaws \Chick"a*saws\, n. pl.; sing. Chickasaw. (Ethnol.)
   A tribe of North American Indians (Southern Appalachian)
   allied to the Choctaws. They formerly occupied the northern
   part of Alabama and Mississippi, but now live in the Indian
   Territory.
   [1913 Webster]