Archean

1 definition found

From WordNet (r) 2.0 [wn]:

  archean
       adj : used of the earliest known rocks [syn: {archaean}]
       n : 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}]