Archean

Từ điển WordNet v3.1 - WordNet Dictionary

noun

the time from 3,800 million years to 2,500 million years ago;
earth's crust formed;
unicellular organisms are earliest forms of life
• Syn:
Archean eon, Archean aeon, Archeozoic, Archaeozoic, Archeozoic eon, Archaeozoic aeon
• Derivationally related forms:
archaeozoic (for: Archaeozoic), archeozoic (for: Archeozoic), archean
• Instance Hypernyms:
eon, aeon
• Part Holonyms:
Precambrian, Precambrian eon, Precambrian aeon, Precambrian period