/ahr'kee euh zoh"ik/ , Geol.
adj.
1. noting or pertaining to the earlier half of the Precambrian Era, from about 5 billion to 2.5 billion years ago, during which the earliest datable rocks were formed and from which the oldest known fossil forms, blue-green algae and bacteria, have been recovered. See table under geologic time .
n.
2. the Archeozoic division of geologic time or the rock systems formed then.
Also, Archaeozoic .
[ 1870-75; ARCHEO- + Gk zo ( é ) life + -IC ]