millennium

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A span of one thousand years.
2. n. A thousand-year period of holiness mentioned in Revelation 20, during which Jesus and his faithful followers are to rule on earth.
3. n. A hoped-for period of joy, serenity, prosperity, and justice.
4. n. A thousandth anniversary.

Century Dictionary and Cyclopedia

1. n. An aggregate of a thousand years; a period or interval of one thousand years: as, the millennium of the occupation of Iceland celebrated in 1874.
2. n. Specifically In theology, a period during which the kingdom of Christ will be established upon the earth and will predominate over all other authority. The phrase “a thousand years,” in Rev. xx. 1-5, has been understood literally, or (on the principle that in Scripture prophecies a day stands for a year, and the Jewish year contained 360 days) as representing 360,000 years. It is generally regarded as indicating an indefinite but long period, and belief in such a period is universal in the Christian church. But whether this predominance of the kingdom of Christ will be accomplished gradually by the gospel, and will precede Christ's second coming, or will follow his second coming and be accomplished by it, is disputed. This question divides theologians into two schools, the postmillenarians, who hold the former view, and the premillenarians, who hold the latter; while many hold that the millennium represents the gospel dispensation or reign of the church, and has accordingly already prevailed for many centuries.

Wiktionary

1. n. A period of time consisting of one thousand years.
2. n. The period of one thousand years during which Christ will reign on earth (according to some interpretations of Revelation 20:1-5).
3. n. A period of universal happiness, peace or prosperity; a utopia.
4. n. The year 2000.

GNU Webster's 1913

1. n. A period of one thousand years.
2. n. The period of a thousand years mentioned in the twentieth chapter of Revelation, during which holiness is to be triumphant throughout the world. Some believe that, during this period, Christ will reign on earth in person with his saints.
3. n. A long period of happiness, righteousness, and prosperity, usually considered as being in the indefinite future.
4. n. A thousandth anniversary Each first day of January falling in a year which is a multiple of one thousand, such as in 1000 a. d. or 2000 a. d..

WordNet 3.0

1. n. (New Testament) in Revelations it is foretold that those faithful to Jesus will reign with Jesus over the earth for a thousand years; the meaning of these words have been much debated; some denominations (e.g. Jehovah's Witnesses) expect it to be a thousand years of justice and peace and happiness
2. n. a span of 1000 years
3. n. the 1000th anniversary (or the celebration of it)