millennium
A period of time consisting of one thousand years.
Other meanings
The year in which one period of one thousand years ends and another begins, especially the year 2000.
“A huge fireworks display was put on in Sydney to celebrate the millennium.”
Any long (and possibly endless) era of universal happiness, peace and prosperity, predicted by various people to come about someday.
Word history
From Latin "mīllennis" (1000-year).
Where this comes from
This definition is adapted from “millennium” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.