millennium

IPA/mɪˈleniəm/
KK[məlˈɛniəm]IPA/mɪˈleniəm/

millennium — noun

  • millenniumsingular
  • millenniumsplural

1. a length of time equal to one thousand years, used especially when talking about

1.nounB2
Definition

a length of time equal to one thousand years, used especially when talking about history, archaeology, or the distant past

Example

The Great Pyramid of Giza has stood for nearly five millennia.

plural form 'millennia' for long time spans

Archaeologists uncovered pottery from a settlement that disappeared more than three millennia ago.

Common collocations
  • a millennium ago
  • over the millennium
  • for millennia
  • three millennia
  • past millennium
Synonyms
  • thousand years

    the everyday equivalent; less formal and more literal than 'millennium'

  • century

    a period of 100 years, not 1,000; used where 'millennium' would be too large a unit

Usage Note

The plural form 'millennia' (from Latin) is the standard in academic and formal writing. 'Millenniums' is accepted in less formal contexts but is far less common.

Common Mistakes

Two millenniums have passed since the last Ice Age
Two millennia have passed since the last Ice Age
The standard Latin plural is 'millennia', not 'millenniums'.
The company has existed for a millennium' (used for 50 years)
The company has existed for half a century
A millennium is exactly 1,000 years, not a loose synonym for 'a very long time.'

2. the year 2000 and the widespread celebrations, cultural changes, and preparation

2.nounB1
Definition

the year 2000 and the widespread celebrations, cultural changes, and preparations that surrounded it, marking the end of the second millennium and the start of the third

Example

Huge crowds gathered in London to welcome the millennium with fireworks and street parties.

welcome the millennium = celebrate the year 2000

The government spent billions fixing computers before the millennium to avoid the Y2K bug.

Common collocations
  • welcome the millennium
  • celebrate the millennium
  • the new millennium
  • millennium celebrations
  • millennium bug
Synonyms
  • Y2K

    informal abbreviation for the year 2000, often referring to the computer bug scare

  • turn of the century

    broader term; can refer to any century change, not specifically the year 2000

Usage Note

Often preceded by 'the' ('the millennium') to refer specifically to the year 2000 transition. The capitalised form 'Millennium' was common in media at the time but has since become less frequent.

Common Mistakes

The new millennium starts in 2001
Most people celebrated the new millennium in 2000
Although the third millennium technically began on 1 January 2001, public celebrations worldwide took place on 31 December 1999.

3. in Christian theology, a future thousand-year period when Christ is expected to

3.nounC1
Definition

in Christian theology, a future thousand-year period when Christ is expected to rule the earth in peace and justice, based on a prophecy found in the Bible's final book

Example

The pastor's sermon explored different views on the millennium found in the Book of Revelation.

the millennium in a religious/theological context

Some early Christian groups believed the millennium would begin within their own lifetimes.

Common collocations
  • the millennium in Revelation
  • views on the millennium
  • the millennium prophecy
  • during the millennium
Synonyms

Usage Note

Typically used with 'the' and often capitalised ('the Millennium') in theological writing. Distinguish from sense 2 (YEAR 2000): this sense refers to a prophesied future reign, not a historical calendar event.

Common Mistakes

The millennium party at church celebrated the year 2000' (when discussing theology)
The church held a conference on the millennium described in Revelation.
The religious sense is about a future reign of Christ, not the year 2000 celebration.

4. a celebration or ceremony held to mark the date exactly one thousand years after

4.nounB2
Definition

a celebration or ceremony held to mark the date exactly one thousand years after the founding of a city, institution, or other significant event

Example

The city of Oxford is preparing for its millennium with a series of events in 2027.

city/institution + millennium = 1000th anniversary

A special postage stamp was issued for the town's millennium celebration.

Common collocations
  • the city's millennium
  • millennium celebrations
  • millennium festival
  • mark the millennium
  • millennium events
Synonyms

Usage Note

Followed by a possessive noun or 'of' phrase ('the city's millennium', 'the millennium of the founding') to specify whose anniversary is being marked.

Common Mistakes

We celebrated the company's millennium with a dinner' (for a 50th anniversary)
We celebrated the company's 50th anniversary with a dinner.
A millennium is 1,000 years, not just a fancy word for 'anniversary.'

Word family

  • millennial
    adjectiveB2
  • millennia
    noun (plural)B2
  • millenarian
    adjectiveC1
  • millenarianism
    nounC1

Synonym discussion

Sense: noun/1

Century, decade, millennium, era, and age all name periods of time, but they differ in precision and scope. Century (100 years) and millennium (1,000 years) have exact fixed lengths and are standard in historical dating — for example, 'the 20th century' or 'the third millennium BCE.' Decade (10 years) is equally precise but spans a shorter period often tied to cultural trends, such as 'the roaring twenties.' Era and age are more flexible: an era can last anywhere from a few years to millions of years and marks a distinct historical or cultural phase ('the colonial era'), while age typically implies a long period defined by a dominant figure or characteristic ('the Ice Age' or 'the age of Shakespeare'). Use millennium when you need a precise 1,000-year unit; use era or age when the time span is approximate and defined by theme.

century ↗decade ↗era ↗age ↗

Common collocations

Nouns

  • millennium celebrations
  • millennium bug
  • millennium project
  • millennium dome

Phrases

  • the turn of the millennium
  • the dawn of the millennium
  • the start of the new millennium

Prepositions

  • in a millennium
  • over the millennium
  • for millennia
  • throughout the millennium
  • during the millennium

Etymology

LatinEnglish

From Latin 'millennium', formed by combining 'mille' (thousand) and 'annus' (year). The word first appeared in English in the early 1600s in religious writings about the thousand-year reign of Christ described in the Book of Revelation. By the 1800s it had broadened beyond theology to mean any period of one thousand years, and later came to refer to the 1,000th anniversary of an event.