Pro·te·ro·zo·ic /ˌprɑtərəˈzoɪk, ˌpro-/
原生地(a.)原生代的
proterozoic
adj : formed in the later of two divisions of the Precambrian era;
"proterozoic life forms"
n : from 2,500 to 544 million years ago; bacteria and fungi;
primitive multicellular organisms [syn: Proterozoic eon,
Proterozoic aeon]