millenary, millennium. the 1000th anniversary (or the celebration of it)
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After one year it's called a cotton wedding anniversary. And after 100 years? Ksheerasagars Lakshman and Lakshmibai of Athani - 160 km from Hubli in Karnataka - wouldn't know. But the 102-year-old barber and his 101-year-old wife crossed that milestone recently.