Pre•cam•bri•anPronunciation: (prē-kam'brē-un, -kām'-), [key] Geol.
noting or pertaining to the earliest era of earth history, ending 570 million years ago, during which the earth's crust formed and life first appeared in the seas. See table under geologic time.
the Precambrian Era. Also,Pre-Cam'bri•an.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.