Source : Webster's Revised Unabridged Dictionary (1913)

Sacs \Sacs\ (s[add]ks), n. pl.; sing. {Sac}. (Ethnol.)
   A tribe of Indians, which, together with the Foxes, formerly
   occupied the region about Green Bay, Wisconsin. [Written also
   {Sauks}.]

Sauks \Sauks\, n. pl. (Ethnol.)
   Same as {Sacs}.