Proterozoic aeon

Thesaurus

Noun

1.Proterozoic aeon - from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organismsProterozoic, Proterozoic eonPrecambrian, Precambrian aeon, Precambrian eon, Precambrian period - the eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago