from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the earliest eon in the history of the Earth from the first accretion of planetary material (around 4,600 million years ago) until the date of the oldest known rocks (about 3,800 million years ago); no evidence of life
Sorry, no etymologies found.
The Hadean has also sometimes been called the Priscoan.