arachnid

noun

arach·nid | \ ə-ˈrak-nəd

, -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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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

While most arachnids live on land, a number of them live in the water. — David Grossman, Popular Mechanics, "Study: Horseshoe Crabs Really Are Arachnids, Just Like Spiders," 28 Feb. 2019 Out of time, the arachnids are likely still full of mysteries. — David Grossman, Popular Mechanics, "Study: Horseshoe Crabs Really Are Arachnids, Just Like Spiders," 28 Feb. 2019 This discovery isn’t necessarily surprising; modern arthropods, like mantises and arachnids, are also well-developed predators from an early age, the researchers note. — Brigit Katz, Smithsonian, "This Prehistoric Sea Creature Had Fanged, Killer Babies," 11 June 2018 So is this one species of spider the only lactating arachnid, or is this behavior more common than scientists thought? — Avery Thompson, Popular Mechanics, "There Is a Spider That Feeds Its Young Delicious Milk, Because Nature Is Scary," 30 Nov. 2018 Six Eyes Add four more eyes to your face for an arachnid aesthetic like Canadian makeup artist Megan Brown. 11. — Devon Abelman, Allure, "27 Last-Minute Halloween Costumes You Can Do With Just Makeup," 10 Oct. 2018 Black widow spiders are considered the deadliest arachnids in the U.S., with a venomous bite about 15 times more potent than a rattlesnake's, according to National Geographic. — Jennifer Earl, Fox News, "Connecticut woman finds black widow spider in bag of grapes," 18 July 2018 Most scientists assumed spiders simply sail on the wind, but this didn’t explain how the arachnids traveled so far in light winds. — Renae Reints, Fortune, "Spiders Can Fly Through the Air for Miles Using Electricity, Study Finds," 6 July 2018 Sméagol, better known as the hobbitses-hating Gollum, is the namesake of yet another arachnid, Landumoema smeagol. — Brigit Katz, Smithsonian, "Introducing a Hairy-Footed Shrimp Named After Bilbo Baggins," 13 June 2018

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.