Definition

Proper noun 1. The Cambrian Period: A major division of geologic time, the first period of the Paleozoic Era, following the Proterozoic Eon and preceding the Ordovician Period. It is characterized by the rapid diversification of multicellular life forms, particularly marine invertebrates, an event known as the Cambrian explosion.

Usage Examples

• Proper noun:
  • The Cambrian Period marks a pivotal point in Earth's biological history.
  • Fossils from the Cambrian Period provide crucial evidence for early animal evolution.
  • Scientists study rock layers dating back to the Cambrian Period.

Advanced Usage

• "The Cambrian": Often used as a shortened form to refer to the Cambrian Period.
  • The fossils are dated to the middle Cambrian.
• "Cambrian explosion": A specific term for the rapid appearance of most major animal phyla in the fossil record during the early Cambrian Period.
  • The Cambrian explosion represents a significant evolutionary event.

Variants and Related Words

• Cambrian (adjective): Of or relating to the Cambrian Period.
  • Cambrian rocks are found on several continents.
• Cambrian (noun): A native or inhabitant of Wales (a different, homographic meaning derived from the Latin name for Wales, ). This is a distinct word and should not be confused with the geologic term.
• Precambrian (adjective/noun): The vast span of time before the Cambrian Period.

Synonyms

• The Cambrian
• Cambrian System (when referring specifically to the sequence of rock strata from this period).

Related Phrases

• "Early/Middle/Late Cambrian": Subdivisions of the Cambrian Period used in more precise geologic dating.
  • These trilobite species are characteristic of the Late Cambrian.

Noun

1. from 544 million to about 500 million years ago; marine invertebrates