Search Result：Proterozoic eon
proterozoic eon 
(TTS Sound)
(TTS Sound)Overview of noun proterozoic_eon
The noun proterozoic eon has 1 sense
- Proterozoic, Proterozoic eon, Proterozoic aeon -- (from 2,500 to 544 million years ago; bacteria and fungi; primitive multicellular organisms)