Definition
"Hadean" relates to Hades, the Greek god of the underworld, or the underworld itself. It can also refer to the Hadean eon, the earliest period in Earth's history. Think of it as anything associated with the realm of the dead or the primordial Earth. It often carries connotations of darkness, mystery, and the unknown. This word is most common in scientific and mythological contexts, not everyday conversation. It is related to something very old and very deep.