Archaean

//ɑːˈkiːən// adj, name, noun

adj, name, noun ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    Any organism of the domain Archaea.
Adjective
  1. 1
    Of or relating to Arche, the Muse of beginnings in Greek mythology. not-comparable
  2. 2
    Of, or relating to the geologic eon from about 4,031 to 2,500 million years ago; comprises the Eoarchean, Paleoarchean, Mesoarchean and Neoarchean eras; marked by an atmosphere with little oxygen, the formation of the first continents and oceans and the emergence of simple life. not-comparable

    "The oldest vestiges of continental crust, which date from the Archaean aeon about 4 billion years ago, are in Acasta in north-west Canada."

  3. 3
    Of or relating to the irregular Jovian moon named for Arche. not-comparable
Adjective
  1. 1
    of or relating to the earliest known rocks formed during the Precambrian Eon wordnet
Proper Noun
  1. 1
    The eon from 2,500 Ma to 4,000 Ma.

Synonyms

All synonyms
archeanearlyhadeanproterozoic

Example

More examples

"The oldest vestiges of continental crust, which date from the Archaean aeon about 4 billion years ago, are in Acasta in north-west Canada."

Etymology

Etymology 1

From Ancient Greek ἀρχαῖα (arkhaîa, “ancient”), neuter plural of ἀρχαῖος (arkhaîos, “ancient”).

Etymology 2

Archaea + -n

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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.