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
: the thousand years mentioned in Revelation (see revelation sense 3) 20 during which holiness is to prevail and Christ is to reign on earth
: a period of great happiness or human perfection
: a period of 1000 years
especially : one reckoned from the beginning of the Christian era
at the start of the third millennium
: 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.

Example Sentences

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 But by the start of the new millennium, other pursuits started pulling them away from being full-time musicians. Robert Ham, SPIN, 12 Jan. 2023 The project was supposed to be a gift to the community to commemorate the dawn of the new millennium until the economy slowed along with donations. Suzanne Baker, Chicago Tribune, 5 Jan. 2023 Will the once-in-a-millennium pope emeritus be buried in them, too? Ashley Fetters Maloy, Washington Post, 31 Dec. 2022 Including Camaros built in an entirely different millennium. Ezra Dyer, Car and Driver, 24 Dec. 2022 And in the past decades, these four have taken their sound around the globe through countless tours and millennium-defying hits. Kenan Draughornestaff Writer, Los Angeles Times, 5 Dec. 2022 This was hardly the first significant English poetry anthology, but Quiller-Couch’s attempt to go panoptic, to view with clarity two-thirds of a millennium of verse, pointed to something new. Brad Leithauser, WSJ, 12 Aug. 2022 People have been chewing the sweet leaves of this Central and South American herb for the better part of a millennium, and researchers are now trying to harness its flavor. Kate Golembiewski, Discover Magazine, 17 June 2019 Even if takes a millennium’s worth of creativity to offset rapacious corporations, unethical developers, ineffective governments and standard-issue corruption. Amy Brady, Scientific American, 12 Dec. 2022 See More

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.

Word History


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

First Known Use

circa 1638, in the meaning defined at sense 1a

Time Traveler
The first known use of millennium was circa 1638

Dictionary Entries Near millennium

Cite this Entry

“Millennium.” Dictionary, Merriam-Webster, Accessed 3 Feb. 2023.

Kids Definition


mil·​len·​ni·​um mə-ˈlen-ē-əm How to pronounce millennium (audio)
plural millennia
or millenniums
: a period of 1000 years
: a 1000th anniversary or its celebration
: a period of great happiness
Last Updated: - Updated example sentences
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