Precambrian

adjective

Pre·​cam·​bri·​an (ˌ)prē-ˈkam-brē-ən  -ˈkām- 

: of, relating to, or being the earliest era of geologic history or the corresponding system of rocks that is characterized especially by the appearance of single-celled organisms and is equivalent to the Archean and Proterozoic eons see Geologic Time Table

Precambrian noun

Word History

First Known Use

1864, in the meaning defined above

Kids Definition

Precambrian

adjective

Pre·​cam·​bri·​an (ˈ)prē-ˈkam-brē-ən 

: of, relating to, or being the earliest era of geological history extending to the beginning of the Phanerozoic eon about 544,000,000 years ago

also : relating to the rocks formed during this time see geologic time

Precambrian noun