arachnid

American  

[uh-rak-nid] / əˈræk nɪd /

noun

• arachnids
  plural

1. any wingless, carnivorous arthropod of the class Arachnida, including spiders, scorpions, mites, ticks, and daddy-longlegs, having a body divided into two parts, the cephalothorax and the abdomen, and having eight appendages and no antennae.

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adjective

1. belonging or pertaining to the arachnids.

arachnid British  

/ əˈræknɪd /

noun

1. any terrestrial chelicerate arthropod of the class Arachnida, characterized by simple eyes and four pairs of legs. The group includes the spiders, scorpions, ticks, mites, and harvestmen

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arachnid Scientific  

/ ə-răk′nĭd /

1. Any of various arthropods of the class Arachnida, such as spiders, scorpions, mites, and ticks. Arthropods are characterized by four pairs of segmented legs and a body that is divided into two regions, the cephalothorax and the abdomen.

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Other Word Forms

Derived Forms

• arachnidan
  adjective

Inflected Forms

Nouns

• arachnids
  plural

Etymology

Origin of arachnid

1865–70; < New Latin Arachnida < Greek aráchn ( ē ) spider, spider's web + New Latin -ida -ida

Explanation

Spiders and scorpions are arachnids. It's a class of animals that also includes tiny, many-legged creatures like mites and ticks. Arachnids are arthropods, or spineless animals with segmented bodies and a shell-like covering. They have a lot in common with crustaceans, but arachnids live on land rather than in the water and don't have antennae. Many varieties of scorpion fall into this category, as well as daddy longlegs (also known as harvestmen). The most common arachnid is a spider — and the word itself derives from the Greek arakhnē, "spider or spider web."

Example Sentences

See Examples For:

arachnid arachnids

The arachnid hormones in his body are surging, causing his pupils to turn black and his temper to explode.

From Los Angeles Times ● Jul. 30, 2026

The latest installment of the Marvel’s arachnid superhero saga sees Tom Holland return as the central character alongside Zendaya, Sadie Sink, Mark Ruffalo, Jacob Batalon and Jon Bernthal.

From The Wall Street Journal ● Jul. 26, 2026

"It's the most emotional Spider-Man movie we've ever made, and in some ways, the most grown up," said Holland, who plays the arachnid superhero.

From Barron's ● Apr. 14, 2026

Emma loves all things arachnid, and goes under various nicknames - spider girl, spider mama, even "weirdo", as her daughter calls her.

From BBC ● May 16, 2025

Just because you’ve called something a spider once doesn’t mean that the next time you have to call it an arachnid or a predaceous eight-legged creepy-crawly.

From "Woe Is I" by Patricia T. O'Conner

Citizen scientists have helped researchers uncover how parental care evolved in harvestmen, a group of spider like arachnids, by contributing observations through the popular nature platform iNaturalist.

From Science Daily ● Jul. 12, 2026

Researchers believe the nocturnal predator developed the unique hunting method to make meals of aggressive ants which are notoriously dangerous - and unusual - prey for arachnids.

From BBC ● Jun. 23, 2026

Golden orb-web spiders are native to southern and east Africa, with the arachnids at Newrotex coming from Madagascar.

From BBC ● Feb. 10, 2026

The researchers say this trend is not slowing and suggest that groups such as plants, fungi, arachnids, fishes and amphibians are far more diverse than previously believed.

From Science Daily ● Dec. 24, 2025

“I can speak to arachnids, including their king, Anansi, of course,” she said with pride.

From "The Marvellers" by Dhonielle Clayton