What are 1000 years called?

A period of 1,000 years is called a millennium. The term is derived from the Latin Words "mille," meaning thousand, and "annus," meaning year. Millennia are often used in historical and cultural contexts to mark significant changes or events over long periods. For example, we recently transitioned from the 2nd millennium (1001-2000) to the 3rd millennium (2001-3000).