What arachnid order includes spiders?

The arachnid order that includes spiders is Araneae. Every modern spider belongs to this order, which sits within the class Arachnida alongside scorpions, harvestmen, mites and several other groups.

Spiders share key features that distinguish them from other arachnids: eight legs, a body divided into a cephalothorax and abdomen, chelicerae often equipped with venom-injecting fangs, and spinnerets that produce silk. Not every spider builds a web, however. Jumping spiders, wolf spiders and many trapdoor spiders hunt in other ways.

Araneae is commonly divided into the suborders Mesothelae and Opisthothelae. Opisthothelae contains the major groups Mygalomorphae, which include tarantulas and trapdoor spiders, and Araneomorphae, which includes most familiar web-building and hunting spiders.

A common mix-up is treating all long-legged or spider-like arachnids as spiders. Harvestmen belong to Opiliones, whip spiders to Amblypygi, and true scorpions to Scorpiones; all are separate orders. The name Araneae comes from Latin aranea, ultimately related to the ancient Greek word for spider.