Precambrian

• Pre-Cambrian

From pre- +‎ Cambrian.

• (Received Pronunciation) IPA^(key): /priːˈkam.bɹɪ.ən/
• (General American) IPA^(key): /priˈkæm.bɹi.ən/
• (Canada) IPA^(key): /priˈkeɪm.bɹi.ən/, /priˈkæm.bɹi.ən/

• Audio (US):

  (file)

• Hyphenation: Pre‧cam‧bri‧an

Precambrian (not comparable)

1. (informal, geology) Relating to the time and geology dated before the Phanerozoic
   • 1981, William Irwin Thompson, The Time Falling Bodies Take to Light: Mythology, Sexuality and the Origins of Culture, London: Rider/Hutchinson & Co., page 209:

     When you look at a Precambrian trilobite in the lobby of a New York bank, it is difficult to speculate about its primeval environment.

Precambrian

1. (geology) The Precambrian supereon; spanning from the formation of the Earth around 4.6 billion years ago to the emergence of hard-shelled creatures 541 million years ago.

• The International Commission on Stratigraphy, which attempts to standardize the vocabulary of the field, is revising the boundaries between time periods based on physical-science methods rather than the kinds of fossils present.
• The boundary between the Precambrian and the Phanerozoic has been changed from time to time and will be subject to change, as will the eons listed as Hyponyms below.

• (geological supereon): Cryptozoic (archaic)

• Phanerozoic

• (geological supereon): Hadean, Archaean, Proterozoic - eons

• (geological supereon): Phanerozoic