archean_eon
1. [ noun ] (geology) the time from 1.5 billion to 5 billion years ago; earth's crust formed; unicellular organisms are earliest forms of life
Synonyms: Archaeozoic Archeozoic_era Archaeozoic_era archaeozoic_aeon archean archean_aeon archeozoic_eon Archeozoic
Related terms: eon era Precambrian
Similar spelling:   archean_aeon
  archean_era
  archaean
  archenteron
  archiannelid
  Archiannelida