millenarianism
Concise Oxford English Dictionary © 2008 Oxford University Press:
millenarianism/mɪlɪˈneəriənɪzəm/
▶noun belief in a future thousand-year age of blessedness, beginning with or culminating in the Second Coming of Christ (central to the teaching of the Adventists, Mormons, and Jehovah's Witnesses).
■ belief in a future utopian period.
– derivatives
millenarianist noun & adjective.
millenarianist noun & adjective.
'millenarianism' also found in these Oxford entries:

