Origin: Latin prefix pre-
Precambrian has 3 different meanings across 2 categories:
the eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago
Relating to the time and geology dated before the Phanerozoic
The eon (or supereon) and rock formations dated before 541.0±1.0 million years ago, coinciding with the first appearance of the fossils of hard-shelled animals.