Arthropods (Greek language for "joint-legged") are a large group of invertebrate animals. Insects, spiders, crabs, shrimp, millipedes, and centipedes are all arthropods. In the scientific classification, all arthropods are members of the phylum Arthropoda. Arthropods have segmented body, an exoskeleton and legs with joints. Most arthropods live on land, but some live in water. Arthropods have by far the greatest number of species of any animal group. Arthropods are a source of food for many animals, including humans.