Adjective: archaean aa(r)'kee-un
- (geology) of or relating to the earliest known rocks formed during the Precambrian Eon
"archaean rocks provide clues about Earth's early history";
- archean [US]
- The time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life
- Archean [US], Archean eon, Archean aeon, Archeozoic, Archaeozoic, Archeozoic eon, Archaeozoic aeon
See also: early
Part of: Precambrian, Precambrian aeon, Precambrian eon, Precambrian period
Encyclopedia: Archaean