The time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life.

synonyms: Archaeozoic, Archaeozoic aeon, Archean, Archean aeon, Archeozoic, Archeozoic eon.

Polish: era azoiczna, archaik, azoik, era archaiczna, archeozoik