S: (n) time period, period of time, period (an amount of time) "a time period of 30 years"; "hastened the period of time of his recovery"; "Picasso's blue period"
S: (n) millennium ((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)
S: (n) millennium, millenary (the 1000th anniversary (or the celebration of it))