Spiders are air-breathing arthropods with eight legs. They have fangs that can inject venom, and spinnerets that release silk. They are the largest order of arachnids. Spiders are found worldwide on every continent except for Antarctica.
Spiders are arthropods, which means they have segmented bodies with jointed limbs, all covered in a cuticle made of chitin and proteins. They are also invertebrates.
Spiders don't have antennae, which are typical of most arthropods.