An arthropod is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Arthropods are members of the phylum Arthropoda (from Greek ἄρθρον árthron, "joint", and ποδός podós "foot", which together mean "jointed feet"), and include the insects, arachnids, crustaceans, and others. --wiki