MILLENNIUM

(plural millennia or millenniums) [noun] [C] - a period of 1000 years, or the time when a period of 1000 years endsThe corpse had lain preserved in the soil for almost two millennia.How will you be celebrating the Millennium?Compare century.The Millennium Bug is a problem with older computers whose clocks are unable to recognise dates after 31 December 1999, with the result that programs might fail to work properly after this date.