noun mil·len·ni·um \mə-ˈle-nē-əm\

: a period of 1,000 years

: a period of a thousand years counted from the beginning of the Christian era

plural -nia \-nē-ə\ or mil·len·niums

Full Definition of MILLENNIUM

a :  the thousand years mentioned in Revelation 20 during which holiness is to prevail and Christ is to reign on earth
b :  a period of great happiness or human perfection
a :  a period of 1000 years; especially :  one reckoned from the beginning of the Christian era <at the start of the third millennium>
b :  a 1000th anniversary or its celebration

Examples of MILLENNIUM

  1. The book describes the changes that have occurred in the landscape over many millennia.
  2. The year 2000 was celebrated as the beginning of the third millennium.


New Latin, from Latin mille thousand + New Latin -ennium (as in biennium)
First Known Use: circa 1638

Other Calendar Terms

antedate, estival, gloaming, luster, sesquicentennial

Rhymes with MILLENNIUM

MILLENNIA Defined for Kids


noun mil·len·ni·um \mə-ˈle-nē-əm\
plural mil·len·nia \-nē-ə\ or millenniums

Definition of MILLENNIUM for Kids

:  a period of 1000 years
:  a 1000th anniversary or its celebration
mil·len·ni·al \-nē-əl\ adjective


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