Milleniarism or Millenniarism: How To spell?
The word Milleniarism is misspelled against Millenniarism, a noun meaning "Belief in, or expectation of, the millennium; millenarianism."
Millenniarism has double "nn" is mispronounced as "n"Remember double 'NN' in between the strings mille & iarism which should not be misspelled with single 'N'
Wrong Spelling:  mille-n-iarism  Correct Spelling:  mille-nn-iarism 
Find more wrongly spelled words of Millenniarism to spell it well.