millennium

American  

[mi-len-ee-uhm] / mɪˈlɛn i əm /

noun

millenniums, plural millennia plural

1. a period of 1,000 years.

   This great stone monument has seen it all—hardship, plenty, and everything in between—over a millennium and a half.

2. the year 2000, or the turn of the 21st century.

   In 1995, approaching the millennium, the city covered nearly 67,000 acres and had a population of over 1 million.

3. Christianity. the millennium, the period of 1,000 years during which Christ will reign on earth, as an interpretation of a vision set forth by the apostle John in the book of Revelation. Also the Millennium

4. a period of general righteousness and happiness, especially in the indefinite future.

5. a thousandth anniversary.

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millennium British  

/ mɪˈlɛnɪəm /

noun

1. Christianity the period of a thousand years of Christ's awaited reign upon earth

2. a period or cycle of one thousand years

3. a time of peace and happiness, esp in the distant future

4. a thousandth anniversary

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millennium Cultural  

1. A period of a thousand years foretold in the Book of Revelation. During the millennium, those who have been faithful to Jesus and who have not worshiped the Antichrist will reign with Jesus over the Earth. According to the Book of Revelation, the millennium will precede the final battle for control of the universe; Judgment Day will come afterward.

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Discover More

Figuratively, a “millennium” is a period of great justice and happiness on Earth.

The meaning of the Bible's (see also Bible) words about the millennium has been much debated by Christians (see also Christian). Prophecies about the millennium are part of the basic doctrine of several denominations, including Jehovah's Witnesses.

Other Word Forms

• millennial
  adjective
• millennialist
  noun
• millennially
  adverb

Etymology

Origin of millennium

First recorded in 1630–40; from New Latin, equivalent to Latin mill(e) “a thousand” + -ennium, extracted from biennium, triennium, etc.

Explanation

A decade means ten years, a century means a hundred, and millennium means a thousand. Think: a decade of marriage, the new millennium. In Latin, in the Romance languages, and in the metric system, mille refers to a thousand. A millimeter is a thousandth of a meter, a milliliter a thousandth of a liter, a millennium is a thousand years. Think of the number "one million" as a thousand thousands, and you'll get the idea.

Example Sentences

Disneyland has added the Mandalorian and Grogu to its Millennium Falcon: Smugglers Run ride.

From Los Angeles Times • May 21, 2026

The show featured red, orange, yellow, pink, blue, blue-green and white diamonds, ranging from 5.11 carats of the Moussaieff Red to 203.04 carats of the De Beers Millennium Star.

From Barron's • May 13, 2026

“Markets ‘moved on’ from the war and oil prices when gas prices stopped going up,” Esther Sholes, senior macro analyst at Take Profit Trader, and former portfolio manager at Millennium Investment Management, told MarketWatch.

From MarketWatch • Apr. 24, 2026

The longer the Millennium drought continues, the more important these findings become.

From Science Daily • Apr. 14, 2026

In Millennium Challenge, this is exactly the mistake that Blue Team made.

From "Blink" by Malcolm Gladwell