Precambrian
adjective
Pre·cam·bri·an
| \ (ˌ)prē-ˈkam-brē-ən
, -ˈkām-
\
, -ˈkām-
\
Definition of Precambrian
: of, relating to, or being the earliest era of geological 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
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