arthropod science definition

Any of numerous invertebrate animals of the phylum Arthopoda, characterized by an exoskeleton made of chitin and a segmented body with pairs of jointed appendages. Arthropods share many features with annelids and may have evolved from them in the Precambrian Era. Arthropods include the insects, crustaceans, arachnids, myriapods, and extinct trilobites, and are the largest phylum in the animal kingdom.