Relatively speaking - the Arachnida

Spiders and their relatives are called arachnids. Arachnids have the head and thorax combined (cephalothorax) with simple eyes, jaws adapted for tearing or piercing prey, a pair of pedipalps and eight walking legs.

Arachnids include spiders, scorpions, pseudoscorpions, whipspiders, harvestmen, ticks and mites.

Spiders are the only arachnids that have special glands in their abdomen which produce silk.