1. [ noun ] 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
Synonyms: hadean_aeon hadean_eon hadean_time priscoan_aeon priscoan_eon hadean
Related terms: eon
Similar spelling:   prison