Hadean time has 2 different meanings across 2 categories:
Noun · Proper 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
The geologic eon from about 4,600 to 3,800 million years ago; marked by the formation of the first rocks.