Arthropod, AHR thruh pod, is any animal that belongs to the major division, or phylum, of the animal kingdom called the Arthropoda. This term is formed from two Greek words, and means jointed feet. Actually, the legs, rather than the feet, are jointed. All the Arthropoda, or arthropods, have jointed legs. Among the most important groups of arthropods are the following: (1) insects, including cockroaches, beetles, bees, butterflies, and many others; (2) crustaceans, including such well-known animals as crabs, lobsters, shrimps, and barnacles; (3) arachnids, including mites, ticks, spiders, and scorpions; (4) chilopods, or centipedes; and (5) diplo-pods, or millipedes. The arthropod phylum contains more than three-fourths of all the different kinds of animals. Insects make up the largest class of arthropods in terms of the number of species.