Source : Webster's Revised Unabridged Dictionary (1913)

Sachem \Sa"chem\ (s[acr"]chem), n.
   A chief of a tribe of the American Indians; a sagamore. See
   {Sagamore}.

Source : WordNet®

sachem
     n 1: a political leader (especially of Tammany Hall)
     2: a chief of a North American tribe or confederation
        (especially an Algonquian chief) [syn: {sagamore}]