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

[From New Latin Arachnida, class name, from Greek arakhnē, spider.]

a·rach′ni·dan (-nĭ-dən) adj. & n.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
They are followed by those of Arachnidan with 9 species and other orders with similar percentages (Table 1).
You feel its arachnidan sting, especially after a delightful shopping spree.
But his epithets arguably pale in comparison with the venality of his predator's arachnidan motives.