PrecambrianWiktionary 原文构词拆分pre-前缀Before; physically in front of. · Before; earlier in time; beforehand.+Cambrian词根/词干词源说明From pre- + Cambrian.释义（英文）形容词 Adjective(informal, geology) Relating to the time and geology dated before the Phanerozoic专有名词 Proper noun(geology) The Precambrian supereon; spanning from the formation of the Earth around 4.6 billion years ago to the emergence of hard-shelled