Millennium

From post-classical Latin millennium, from Latin mÄ«lle ("thousand") + -ennium (from annus ("year")).

Full definition of millennium

(plural millennia or millenniums)

2013, Dan Pearson, The Guardian, 24 Mar 2013:Magnolias are some of the most primitive of our flowering trees, and fossils dating back millennia prove that they have had little need to evolve.

(Christianity) The period of one thousand years during which Christ will reign on earth (according to Millenarianist interpretations).

1911, Saki, â€˜Tobermoryâ€™, The Chronicles of Clovis:An archangel ecstatically proclaiming the Millennium, and then finding that it clashed unpardonably with Henley and would have to be indefinitely postponed, could hardly have felt more crestfallen than Cornelius Appin at the reception of his wonderful achievement.
1971, Keith Thomas, Religion and the Decline of Magic, Folio Society 2012, p. 137:the end of the world would be heralded by a series of spectacular and symbolic events â€¦. According to most commentators, this millennium had already begun.
2011, Norman Davies, Vanished Kingdoms, Penguin 2012, p. 117:Conrad's later years unfolded in the shadow of the coming Millennium, when the end of the world was forecast.

1902, William James, The Varieties of Religious Experience, Folio Society 2008, p. 318:But the aggressive members of society are always tending to become bullies, robbers, and swindlers; and no one believes that such a state of things as we now live in is the millennium.

(with definite article) The year in which one period of one thousand years ends and another begins, especially the year 2000.