[ uh-rak-nid ]
/ əˈræk nɪd /


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.Compare insect.


belonging or pertaining to the arachnids.

Origin of arachnid

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


a·rach·ni·dan [uh-rak-ni-duh n] /əˈræk nɪ dən/, adjective, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for arachnid

British Dictionary definitions for arachnid

/ (əˈræknɪd) /


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

Derived forms of arachnid

arachnidan, adjective, noun

Word Origin for arachnid

C19: from New Latin Arachnida, from Greek arakhnē spider
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for arachnid

[ ə-răknĭd ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.