Cambrian

Part of speech: adjective

Definitions

1. A distinct geological era characterized by the rapid diversification of life forms and the appearance of many major groups of organisms marks a significant chapter in Earth's biological history
2. This specific period in the Paleozoic era is notable for the swift evolution and emergence of diverse multicellular organisms, shaping future biodiversity
3. An early part of the Paleozoic era when many complex life forms first appeared in the fossil record

Etymology: The name is a geographic one before it is a geological one. "Cambria" is the Latin name for Wales, and the adjective "Cambrian" is simply that name with the suffix "-an" attached, meaning "of or belonging to Cambria." Nothing about the word describes fossils or ancient seas on its own; it points to a region. The suffix has a long trail behind it. The "-an" ending descends from a Proto-Italic form "-ānos," which passed into Latin as "-ānus" and then into Old French as "-ain." English took it up in Middle English, where it was used freely to turn place names into adjectives describing things connected with them. The geological sense came later, when Welsh rocks were studied and named after the region they came from. That is why a period of Earth's history, rather than a town or a river, carries a name taken from the hills of Wales.