noun.
The 2,000th anniversary of an event or happening.
adjective.
Occurring every thousand (2,000) years and 2 millennia.
Word Usage
"In an ingenious and thought-provoking paper some time ago, Jerrold Levinson put forward a novel and imaginative thesis purporting to explain why tropism never quite got off the ground, despite its respectable bimillennial launch history (1980)."