archaeozoic

(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. Synonyms: Archean, Archean eon, Archean aeon, Archeozoic, Archaeozoic, Archeozoic eon, Archaeozoic aeon.

(adj) of or belonging to earlier of two divisions of the Precambrian era. Synonyms: archeozoic. Example: "Archeozoic life forms."