arachnid

/əˈræknɪd/

/əˈræknɪd/

Other forms: arachnids

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."

Definitions of arachnid

1. noun

   an arthropod with simple eyes and four pairs of legs
   synonyms: arachnoid

   types:

   Phalangium opilio, daddy longlegs, harvestman

   spiderlike arachnid with a small rounded body and very long thin legs

   scorpion

   arachnid of warm dry regions having a long segmented tail ending in a venomous stinger

   false scorpion, pseudoscorpion

   small nonvenomous arachnid resembling a tailless scorpion

   whip scorpion, whip-scorpion

   nonvenomous arachnid that resembles a scorpion and that has a long thin tail without a stinger

   spider

   predatory arachnid with eight legs, two poison fangs, two feelers, and usually two silk-spinning organs at the back end of the body; they spin silk to make cocoons for eggs or traps for prey

   acarine

   mite or tick

   Chelifer cancroides, book scorpion

   minute arachnid sometimes found in old papers

   Mastigoproctus giganteus, vinegarroon

   large whip-scorpion of Mexico and southern United States that emits a vinegary odor when alarmed

   orb-weaving spider

   a spider that spins a circular (or near circular) web

   Argiope aurantia, black and gold garden spider

   a widely distributed North American garden spider

   Araneus cavaticus, barn spider

   an orange and tan spider with darkly banded legs that spins an orb web daily

   Aranea diademata, garden spider

   a spider common in European gardens

   comb-footed spider, theridiid

   spider having a comb-like row of bristles on each hind foot

   Latrodectus mactans, black widow

   venomous New World spider; the female is black with an hourglass-shaped red mark on the underside of the abdomen

   tarantula

   large hairy tropical spider with fangs that can inflict painful but not highly venomous bites

   hunting spider, wolf spider

   ground spider that hunts its prey instead of using a web

   trap-door spider

   American spider that constructs a silk-lined nest with a hinged lid

   tick

   any of two families of small parasitic arachnids with barbed proboscis; feed on blood of warm-blooded animals

   mite

   any of numerous very small to minute arachnids often infesting animals or plants or stored foods

   type of:

   arthropod

   invertebrate having jointed limbs and a segmented body with an exoskeleton made of chitin