mil·​len·​ni·​um | \ mə-ˈle-nē-əm How to pronounce millennium (audio) \
plural millennia\ mə-​ˈle-​nē-​ə How to pronounce millennium (audio) \ or millenniums

Definition of millennium

1a : the thousand years mentioned in Revelation (see revelation sense 3) 20 during which holiness is to prevail and Christ is to reign on earth
b : a period of great happiness or human perfection
2a : a period of 1000 years especially : one reckoned from the beginning of the Christian era at the start of the third millennium
b : a 1000th anniversary or its celebration In 2015 the city of Leipzig, Germany, celebrated its millennium.

Did you know?

Since in Latin mille means "thousand", a millennium lasts 1,000 years. Thus, we're living today at the beginning of the third millennium since the birth of Christ. But some religious sects, relying on a prophecy in the biblical Book of Revelation, speak of a coming millennium when Jesus will return to reign on earth for 1,000 years, evil will be banished, and all will live in peace and happiness. Members of these sects who keep themselves in a constant state of preparedness are called millenarians or millennialists.

Examples of millennium in a Sentence

The book describes the changes that have occurred in the landscape over many millennia. The year 2000 was celebrated as the beginning of the third millennium.
Recent Examples on the Web The camel reliefs at the Camel Site were dated to the sixth millennium bc. Rafil Kroll-zaidi, Harper's Magazine, 23 Nov. 2021 There was genuine concern chaos would break out in the streets and the world would look terribly different when the show ended and the new millennium dawned. Los Angeles Times, 17 Nov. 2021 The Ford Focus nameplate was new for the new millennium, and Ford’s global small car was quickly granted entry into the 10Best club for 2000. Alexander Stoklosa, Car and Driver, 17 Nov. 2021 Hyperventilating techies proclaim that the millennium has arrived, even while battling over which models are actually worth upgrading to compared with cheaper alternatives. Joe Queenan, WSJ, 4 Nov. 2021 Trump really did make four years seem like a millennium, which is probably how Ruffin managed to pack what felt like 1,000 years of heresy into one song. Bethy Squires, Vulture, 15 Oct. 2021 But there is nothing in nature that corresponds to a decade—or a century, or a millennium. The New Yorker, 11 Oct. 2021 To those who believe A.I. is among the most transformative technologies of the last century, millennium, or even epoch, its role in tackling the pandemic has been a disappointment. Jeremy Kahn, Fortune, 28 Sep. 2021 At this point, the Clinton administration had been through the first world trade center bombing, the African embassy bombings, the millennium threats, and now the attack on the Cole. CBS News, 15 Sep. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'millennium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of millennium

circa 1638, in the meaning defined at sense 1a

History and Etymology for millennium

New Latin, from Latin mille thousand + New Latin -ennium (as in biennium)

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Time Traveler for millennium

Time Traveler

The first known use of millennium was circa 1638

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Last Updated

27 Nov 2021

Cite this Entry

“Millennium.” Dictionary, Merriam-Webster, Accessed 2 Dec. 2021.

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English Language Learners Definition of millennium

: a period of 1,000 years
: a period of a thousand years counted from the beginning of the Christian era


mil·​len·​ni·​um | \ mə-ˈle-nē-əm How to pronounce millennium (audio) \
plural millennia\ -​nē-​ə \ or millenniums

Kids Definition of millennium

1 : a period of 1000 years
2 : a 1000th anniversary or its celebration

Other Words from millennium

millennial \ -​nē-​əl \ adjective


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