Priscoan aeon and Priscoan eon

Priscoan aeon 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.

Priscoan eon and Priscoan aeon are semantically related. In some cases you can use "Priscoan eon" instead a noun phrase "Priscoan aeon".

Priscoan eon 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.

Priscoan aeon and Priscoan eon are semantically related. You can use "Priscoan aeon" instead a noun phrase "Priscoan eon".