There are many distinguishing features that separate the arthropods from any other phylum. The word “arthropod” comes from two Greek words, arthros, meaning jointed, and pods, meaning feet. The members of this phylum are easily recognizable because of their jointed appendages.
All arthropods have a distinct head, which is sometimes merged with the thorax to form a large structure called the cephalothorax. The cephalothorax contains all mouthparts, including the antennae and the thoracic appendages, and is covered by a protective exoskeleton called a carapace. The cephalothorax is easily the most distinguishing feature of the arthropod phylum.