hunkpapa: a member of the Siouan people who constituted a division of the Teton Sioux and who formerly lived in the western Dakotas; they were prominent in resisting the white encroachment into the northern Great Plains
teton: a member of the large western branch of Sioux people which was made up of several groups that lived on the plains
hardening: the act of making something harder (firmer or tighter or more compact)