Acarus

n. minute spider-like animal, mite

Mites, including ticks, belong to the subclass Acarina (also known as Acari) and the class Arachnida. Mites are among the most diverse and successful of all the invertebrate groups. They have exploited an incredible array of habitats, and because of their small size (most are microscopic) most go totally unnoticed. Many live freely in the soil or water, but there are also a large number of species that live as parasites on plants or animals and even some that feed on mold.
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Noun
1. a mite of the genus Acarus
(hypernym) mite
(member-holonym) Acarina, order Acarina

n. acarus, minute spider-like animal, mite

(n.)
A genus including many species of small mites.