immunity - Freedom or exemption from some imposition “…[the] militia massacred four hundred Indians who apparently thought they had been promised immunity."

medicine man - Among native Americans, a holy man or shaman who exercises spiritual powers and is considered able to cure disease. “…among their leaders was heavyset Sitting Bull, a medicine man as wily as he was influential."

reservation - Public land designated for use by native Americans. "The vanquished native Americans were finally ghettoized in `human zoos' known as reservations....

ward - Someone considered incompetent to manage his or her own affairs and therefore placed under the legal guardianship of another person or group."… there [they had] to eke out a sullen existence as wards of the government."

probationary - Concerning a period of testing or trial, after which a decision is made based on performance. "The probationary period was later extended. . . ."

folklore - The common traditions and stories of a people. "These bowlegged Knights of the Saddle became an authentic part of American folklore."

irrigation - Watering land artificially, through canals, pipes, or other means. "Improved irrigation techniques . . . caused deserts to bloom . . ."

meridian - In geography, any of the lines of longitude running north and south on the globe. "The farmers rashly pushed beyond the 100th meridian...”

contiguous - Joined together by common borders. "Only Oklahoma, New Mexico, and Arizona remained to be lifted into statehood from contiguous territory on the mainland of North America."

safety valve - Anything, such as the American frontier, that allegedly serves as a necessary outlet for  built-up pressure, energy, and so on. "But the `safety-valve' theory does have some validity."

loan shark - A person who lends money at an exorbitant or illegal rate of interest. "The [farmers] cried out in despair against the loan sharks... ."

serfdom - The feudal condition of being permanently bound to land owned by someone else. “... the farmers were about to sink into a status suggesting Old World serfdom."

mumbo jumbo - Mysterious and unintelligible words or behavior. "Kelley... introduced a mumbo jumbo of passwords and secrecy…"

prophet - A person believed to speak with divine power or special gifts. "Numerous fiery prophets sprang forward..."

citadel - A fortress occupying a commanding height. "They would soon join their fellow farmers in the South in a ferocious attack on the northeastern citadels of power."