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

While the mechanics of trilobite enrollment are well studied, these observations have only been made by examining their exoskeletons due to a lack of enrolled fossils with soft tissue preservation.

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

Even more awkwardly anomalous was another species of trilobite found in Europe and the Pacific Northwest but nowhere in between, which would have required not so much a land bridge as a flyover.

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