始し生せい代だい

noun

Archaeozoic Era; Archeozoic Era

Geological term for the early Precambrian era when life first appeared. Used mainly in scientific contexts.

• 始し生せい代だいは約やく40億おく年ねん前まえから25億お年くねん前まえまでの時じ代だいを指さす。

  The Archaeozoic Era refers to the period from about 4 billion to 2.5 billion years ago.