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

"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

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

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

The arachnid awakening is part of a cascade of weather-dependent events, explained Lisa Gonzalez, program manager of invertebrates for L.A.

From Los Angeles Times • Aug. 7, 2024

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