arach·​nid | \ ə-ˈrak-nəd How to pronounce arachnid (audio) , -ˌnid \

Definition of arachnid

: any of a class (Arachnida) of arthropods comprising chiefly terrestrial invertebrates, including the spiders, scorpions, mites, and ticks, and having a segmented body divided into two regions of which the anterior bears four pairs of legs but no antennae

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Other Words from arachnid

arachnid adjective

Did You Know?

The term arachnid refers to a class of animals that includes spiders, scorpions, mites, and ticks. Most arachnids have a segmented body divided into two regions, with the front part bearing four pairs of legs, but no antennae. They have a hard external skeleton and range in size from the mite, which is 0.003-in (0.08-mm) long, to the 8-in (21-cm) black scorpion of Africa. As arachnids grow, they molt, or shed their skin, several times. Arachnids are primarily carnivorous, but most are unable to digest food internally, instead they inject their prey with digestive fluids, then suck the liquefied remains. Arachnids are found worldwide in nearly every habitat. Some mites and ticks are parasitic and can carry diseases. Venomous spiders and scorpions also may pose a danger to humans, but most arachnids are harmless and prey only on insects.

Examples of arachnid in a Sentence

Spiders, scorpions, mites, and ticks are arachnids.
Recent Examples on the Web Arlington’s River Legacy Nature Center will host the largest arachnid display in North America when a new exhibit opens Dec. 1. Brayden Garcia, Dallas News, "No social distancing required with these spiders and scorpions in Arlington, if that’s your thing," 23 Nov. 2020 The red design on the arachnid's back mirrors the red lipstick stain on her lip. Nick Romano,, "American Horror Stories anthology spin-off cracks open first creepy teaser poster," 12 Nov. 2020 The web was made by an orb weaver spider, an arachnid known for its intricate web designs. Lauren M. Johnson, CNN, "Spooky spiderweb found in Missouri looks big enough to 'catch' a human," 3 Oct. 2020 But why the insect-eating Australian arachnid’s venom evolved to become deadly to humans, which are neither predator nor prey of the spiders, was something of a mystery. Alex Fox, Smithsonian Magazine, "Deadly Spiders Evolved Venom to Safely Search for Love," 25 Sep. 2020 Those round shells and long legs give Japanese spider crabs an arachnid-like look, hence their common name. National Geographic, "Japanese spider crab," 16 Sep. 2020 Video and images of an engorged arachnid clinging to the door of an Texas apartment last week have gone viral. Fox News, "Massive spider found clinging to Texas home: 'I was terrified!'," 25 June 2020 In his research, Dr. Platnick focused on Oonopidae, a family of tiny arachnids also known as goblin spiders, which generally measure less than two millimeters in length. John Schwartz, New York Times, "Norman Platnick, the ‘Real Spider-Man,’ Is Dead at 68," 17 Apr. 2020 What really matters is that panfish—and bluegill especially—will chomp a sponge arachnid even when the bite is slow. T. Edward Nickens, Field & Stream, "The Best Flies for Catching Panfish," 12 Mar. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'arachnid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of arachnid

1826, in the meaning defined above

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Time Traveler for arachnid

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The first known use of arachnid was in 1826

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Cite this Entry

“Arachnid.” Dictionary, Merriam-Webster, Accessed 26 Feb. 2021.

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English Language Learners Definition of arachnid

technical : a kind of animal that has eight legs and a body formed of two parts

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Nglish: Translation of arachnid for Spanish Speakers Encyclopedia article about arachnid

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