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

"These were the first known complete trilobite appendages," said Losso, "before their discovery in the late 1800s, scientists knew of the walking leg, but not what the gill branches looked like."

From Science Daily • Dec. 21, 2023

Discovered by the paleontologist Charles Doolittle Walcott in 1870, the site yielded the first traces of trilobite appendages and soft-tissue features like gills.

From New York Times • Dec. 19, 2023

“While enrolled trilobite fossils are really common, we don’t have any of the ventral soft tissue preserved,” said Sarah Losso, a Ph.D. candidate at Harvard University who specializes in trilobite evolution.

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

I was hefting a trilobite fossil and half listening.

From "The Evolution of Calpurnia Tate" by Jacqueline Kelly