Proterozoic (redirected from Proterozoic eon)
Also found in: Dictionary
Related to Proterozoic eon: Hadean eon
, Archean eon
, Paleozoic era
, Phanerozoic eon
Proterozoic that period of geological time lasting from some 2600 million to 589 million years ago; the part of Cryptozoic time excluding the Archaean Period. Fossils dating from this period are mainly CYANOBACTERIA.