1. epoch-making

adjective. highly significant or important especially bringing about or marking the beginning of a new development or era.

Rhymes with Eocene Epoch

2. Eocene

noun. from 58 million to 40 million years ago; presence of modern mammals.

3. epoch

noun. ['ˈɛpək, ˈiːpək'] a period marked by distinctive character or reckoned from a fixed point or event.

4. epoch

noun. ['ˈɛpək, ˈiːpək'] (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded.

5. epoch

noun. ['ˈɛpək, ˈiːpək'] a unit of geological time that is a subdivision of a period and is itself divided into ages.