Cambrian
adjective
Cam·bri·an ˈkam-brē-ən 
ˈkām-
ˈkām- 1
: welsh
2
: of, relating to, or being the earliest geologic period of the Paleozoic era or the corresponding system of rocks marked by fossils of nearly every major invertebrate animal group see Geologic Time Table
Cambrian noun
Word History
Etymology
Medieval Latin Cambria Wales, from Middle Welsh Cymry Wales, Welshmen
First Known Use
1603, in the meaning defined at sense 1