English Dictionary

Proterozoic

name

(geology) The eon from 2,500 Ma to 541.0±1.0 Ma, the beginning of the Phanerozoic, marked by the build up of oxygen in the atmosphere and the emergence of primitive multicellular life.

The Proterozoic is a name given to the eon from 2.5 billion to 541 million years ago.

意味（1）

(geology) The eon from 2,500 Ma to 541.0±1.0 Ma, the beginning of the Phanerozoic, marked by the build up of oxygen in the atmosphere and the emergence of primitive multicellular life.