arachnid

American  

[uh-rak-nid] / əˈræk nɪd /

noun

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

• arachnidan adjective

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

A map of the routes with arrows arching across the country gave the operation its arachnid moniker.

From The Wall Street Journal • Dec. 10, 2025

As Ms Teni offloads one arachnid that was delivered to her in a Vegemite jar, she stresses her team isn't telling Australians to go looking for the spiders and "throw themselves into danger".

From BBC • May 16, 2025

For Waterhouse, the discovery of the arachnid wasn’t just throwaway internet fodder — it became a metaphor for her own memoir and, in turn, “Memoir of a Sparklemuffin,” due Sept. 13 on Sub Pop.

From Los Angeles Times • Sep. 13, 2024

This led the two scientists to conclude it doesn't belong in any of the known arachnid orders.

From Science Daily • May 17, 2024

It skittered back a few yards, and Gregor got his first good look at the arachnid.

From "Gregor the Overlander" by Suzanne Collins