Since in Latin mille means "thousand", a millennium lasts 1,000 years. Thus, we're living today at the beginning of the third millennium since the birth of Christ.

A millennium (pl. millennia or millenniums) is a period of one thousand years, one hundred decades, or ten centuries, [1][2] It is also sometimes called a kiloannum (ka) or kiloyear (ky).

MILLENNIUM definition: 1. a period of 1,000 years, or the time when a period of 1,000 years ends: 2. the beginning of a…. Learn more.

MILLENNIUM definition: a period of 1,000 years. See examples of millennium used in a sentence.

Definition of millennium noun from the Oxford Advanced Learner's Dictionary. a period of 1 000 years, especially as calculated before or after the birth of Christ. For millennia, it was accepted …

1. a. a period of 1000 years. b. one of the successive periods of 1000 years reckoned forward or backward from the assumed date of the birth of Jesus. 2. the millennium, the period of 1000 …

A millennium is a period of one thousand years, especially one which begins and ends with a year ending in '000', for example the period from the year 1000 to the year 2000.

Dec 14, 2025 · Noun [edit] millennium (plural millennia or millenniums) (countable) A period of time consisting of one thousand years. synonyms, coordinate terms quotations Synonyms: …

Factsheet What does the noun millennium mean? There are four meanings listed in OED's entry for the noun millennium. See ‘Meaning & use’ for definitions, usage, and quotation evidence.

A decade means ten years, a century means a hundred, and millennium means a thousand. Think: a decade of marriage, the new millennium.