millennium /məˈlɛnijəm/ noun plural millennia /-nijə/ /məˈlɛnijə/ or millenniums plural millennia /-nijə/ /məˈlɛnijə/ or millenniums Learner's definition of MILLENNIUM
[count]
1
: a period of 1,000 years一千年 2
: a period of a thousand years counted from the beginning of the Christian era(公元纪年)千年期 — millennial
/məˈlɛnijəl/ adjective