Millennium

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

The issue arises from the difference between the convention of using ordinal numbers to count years and millennia, as in "the third millennium", or using a vernacular description, as in "the two thousands".

The first convention is common in English-speaking countries, but the latter is favoured in, for example, Sweden (tvåtusentalet, which translates literally as the two thousands period).

[6] Stephen Jay Gould, in his essay "Dousing Diminutive Dennis' Debate (or DDDD = 2000)", discussed the "high" versus "pop" culture interpretation of the transition.

[11] The popular[12] approach was to treat the end of 1999 as the end of "a millennium" and to hold millennium celebrations at midnight between December 31, 1999, and January 1, 2000, with the cultural and psychological significance of the events listed above combining to cause celebrations to be observed one year earlier than the formal date.