arachnid

noun

arach·​nid ə-ˈrak-nəd How to pronounce arachnid (audio)
-ˌnid
: 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
arachnid adjective

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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 The spiders themselves are curious and inquisitive, and they are favored among arachnid admirers for their cleverness and their adorable, almost friendly appearance. Sam Walters, Discover Magazine, 3 Jan. 2024 Like many other cave creatures, these arachnids sport noticeably undeveloped eyes. Jack Tamisiea, Scientific American, 20 Dec. 2023 Colossus, the male funnel-web spider, was the last arachnid to hold the record for ARP's largest male in the antivenom program. Esme Mazzeo, Peoplemag, 5 Jan. 2024 The arachnid lies still, sprawled across the floor with one of its six legs pointed in each direction. Ron Lieber, New York Times, 16 Dec. 2023 But what are the banes of this tiny arachnid that can humble the apex predator? Paul Richards, Field & Stream, 9 Nov. 2023 In the past six years, the arachnids have spread across 19 states, colonizing new areas incredibly quickly thanks to an unusual reproductive strategy called parthenogenesis. Margaret Osborne, Smithsonian Magazine, 27 Nov. 2023 The following day, Doja unveiled a second cover — this time of a gouache watercolor painting of two arachnids. Emily Zemler, Rolling Stone, 15 Sep. 2023 The two records, both due out on September 22, originally bore artwork featuring paintings of dark pink arachnids beneath a dot of liquid. Jazz Monroe, Pitchfork, 31 Aug. 2023 See More

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'arachnid.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1826, in the meaning defined above

Time Traveler
The first known use of arachnid was in 1826

Dictionary Entries Near arachnid

Cite this Entry

“Arachnid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/arachnid. Accessed 4 Mar. 2024.

Kids Definition

arachnid

noun
arach·​nid ə-ˈrak-nəd How to pronounce arachnid (audio)
-ˌnid
: any of a class of arthropods including the spiders, scorpions, mites, and ticks and having a segmented body divided into two regions of which the front part bears four pairs of legs but no antennae
arachnid adjective

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