1. The era during which, or during the latter part of which, the oldest system of rocks was made. 2. The last of three subdivisions of Archean time, when the lowest forms of life probably existed; as more physical measurements of geologic time are made, the usage is changing; it is now considered part of the Early Precambrian. 3. The archeozoic period was the first geological period. It was characterised by an absence of animal life and extensive volcanic activity.
Related terms: