trilobite

American  

[trahy-luh-bahyt] / ˈtraɪ ləˌbaɪt /

noun

1. any marine arthropod of the extinct class Trilobita, from the Paleozoic Era, having a flattened, oval body varying in length from 1 inch (2.5 centimeters) or less to 2 feet (61 centimeters).

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trilobite British  

/ ˈtraɪləˌbaɪt, ˌtraɪləˈbɪtɪk /

noun

1. any extinct marine arthropod of the group Trilobita , abundant in Palaeozoic times, having a segmented exoskeleton divided into three parts

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trilobite Scientific  

/ trī′lə-bīt′ /

1. Any of numerous extinct and mostly small arthropods of the subphylum Trilobita that lived during the Paleozoic Era and are extremely common as fossils. Trilobites had a hard outer covering divided into three lengthwise and three widthwise sections. Their heads had two prominent compound eyes similar in structure to those of modern insects.

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Other Word Forms

• trilobitic
  adjective

Etymology

Origin of trilobite

First recorded in 1825–35; from New Latin Trilobites, equivalent to Greek trílob(os) “three-lobed” + -ītēs noun suffix; see tri-, lobe, -ite ¹

Explanation

A trilobite is a type of fossil. Trilobites were arthropods — small, segmented animals with exoskeletons — that lived in Paleozoic times. Trilobites were marine animals with many legs, their bodies divided into segments (like spiders, scorpions, and caterpillars). The back of a trilobite's body had three sections, or lobes. The word trilobite, in fact, means "three lobes" in Greek, from tri and lobos. We know a lot about trilobites, especially considering they've been extinct for a long time, because their exoskeletons were easily fossilized.

Example Sentences

"And then I came across something we never see in trilobite fossils."

From Science Daily • Dec. 21, 2023

Ms. Losso was analyzing the trilobites’ appendages when she came across a curled Ceraurus trilobite with a set of plates called sternites lining its stomach that rarely survives fossilization.

From New York Times • Dec. 19, 2023

Walcott’s trilobite fossils, and thin sections he sliced out of them, are stored at the Museum of Comparative Zoology at Harvard University.

From New York Times • Dec. 19, 2023

The trilobite fossils were trapped between layers of petrified ash in sandstone, the product of old volcanic eruptions that settled on the sea floor and formed a green layer called a tuff.

From Science Daily • Nov. 21, 2023

One species of trilobite that was well known in Europe was also found to have lived on Newfoundland–but only on one side.

From "A Short History of Nearly Everything" by Bill Bryson