from Wiktionary, Creative Commons Attribution/Share-Alike License.
- adjective geology Of a
geologic erawithin the Archaean eonfrom about 4600 to 3600 million years ago; the first single- celled lifebegan at this time.
- noun geology The Eoarchean era.
Sorry, no etymologies found.
Though commonly used, the Hadean is not a formal eon and no lower bound for the Eoarchean has been agreed upon.