From Latin 'mille' (thousand) + 'annus' (year) — originally a theological term for Christ's prophesied thousand-year reign.
A period of one thousand years; (in Christian theology) the thousand-year reign of Christ prophesied in the Book of Revelation. Plural: millennia or millenniums.
From Modern Latin millennium, constructed from Latin mille (thousand) and annus (year). Mille derives from PIE *gheslo- (thousand), reconstructed from Sanskrit sahasra, Greek khilioi, and Latin mille — the forms are not directly cognate but share the general semantic field. Annus (year) comes from PIE *at-no- (year, period of going), related to Gothic aþnam (years
The word 'mile' comes from Latin 'mīlle passūs' (a thousand paces). A Roman mile was literally a thousand double-steps — about 1,480 meters, slightly shorter than the modern statute mile. The same Latin 'mille' (thousand) gives us 'million' (a 'great thousand,' from Italian 'milione,' an augmentative of 'mille'), 'millipede' (thousand-footed