Archaean

== English == === Alternative forms === Archean Archæan (archaic) === Etymology === From Ancient Greek ἀρχαῖα (arkhaîa, “ancient”), neuter plural of ἀρχαῖος (arkhaîos, “ancient”). === Pronunciation === (Received Pronunciation) IPA(key): /ɑːˈkiːən/ (General American) IPA(key): /ɑɹˈkiːən/ Rhymes: -iən === Adjective === Archaean (not comparable) (mythology) Of or relating to Arche, the Muse of beginnings in Greek mythology. (geology) 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. (astronomy, "Archean" only) Of or relating to the irregular Jovian moon named for Arche. ==== Translations ==== === Proper noun === Archaean (geology) The eon from 2,500 Ma to 4,000 Ma. ==== Hypernyms ==== (eon 2,500–4,000 Ma): Precambrian ==== Hyponyms ==== (eon 2,500–4,000 Ma): Eoarchaean, Paleoarchaean, Mesoarchaean, Neoarchaean ==== Coordinate terms ==== (eon 2,500–4,000 Ma): Hadean, Proterozoic - eons in Precambrian ==== Translations ==== === See also === Appendix:Geologic timescale === Further reading === Archaean on Wikipedia.Wikipedia