Millennialist n. One who believes that Christ will reign personally on earth a thousand years; a Chiliast; also, a believer in the universal prevalence of Christianity for a long period.
... word, nor a Bible doctrine. It is a word and teaching of the apostasy. The word is used to denote a thousand years. The most general teaching of the millennialist is that there will be a personal reign of Christ upon this earth of a thousand years after his second coming. There are very many theories respecting the millennium. This of itself is enough to make the doctrine very questionable. ... — The Gospel Day • Charles Ebert Orr