Erathem

Erathem is a term that appears only in a small number of fringe discussions and speculative writings, where it is proposed as a unit of time larger than a conventional era. In these contexts, an erathem is described as a broad temporal container that could span multiple eras or mark a foundational phase in a planet’s, biosphere’s, or cosmos’s history. Because it is not part of established geologic or cosmological nomenclature, there is no standard definition or measurement associated with the term.

Etymology and history: The word is not attested in standard dictionaries or in formal scientific usage, and its exact origin remains uncertain. Some authors coin or repurpose the term within private glossaries or fictional works, without broad consensus on its meaning or scope.

Usage and reception: The term remains obscure and is not used in authoritative references. In mainstream geoscience and astronomy, researchers continue to rely on the conventional hierarchy of eon, era, period, epoch, and age. When erathem is mentioned, it is typically within speculative or fictional contexts rather than as a formally defined unit in established science.

See also: Geologic time scale, Eon, Era, Period, Epoch, Chronology, Time scale, Speculative fiction.