Although spiders are classified as both arthropods and arachnids, neither of those is the family name. Arthropoda is the phylum to which spiders belong, while arachnid is the class. No one family exists to which all spiders belong.
At least 112 spider families in the order Araneae (true spiders) have been identified. The arrangement of a spider's eyes is one characteristic that determines its family. Arachnids have a two-part body, eight legs and no antennae. Other creatures in this class are scorpions, mites and ticks. Arthropods are invertebrates with a segmented body and jointed legs. This phylum includes insects and arachnids.