millennium
n 1: a span of 1000 years
2: (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
3: the 1000th anniversary (or the celebration of it)
[also: millennia (pl)]