Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

English definition of “millennium”


noun [C]    /məˈlen·i·əm/ (plural millennia  /məˈlen·i·ə/ or millenniums)
a period of 1000 years: The area has experienced the worst drought in half a millennium. millennial    /məˈlen·i·əl/ adjective [not gradable]
(Definition of millennium noun from the Cambridge Academic Content Dictionary © Cambridge University Press)
Focus on the pronunciation of millennium

Definitions of “millennium” in other dictionaries

Word of the Day


a person or group who receives money, advantages, etc. as a result of something else

Word of the Day


Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More