Era was a time of great change and progress. It was a period of exploration, discovery, and innovation, with advances in science, technology, and culture. It was a time of great social and political upheaval, with revolutions and wars that shaped the world we live in today. It
From Wikipedia
An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth.