What is arthropod segment?

Arthropods are a category of invertebrate characterized by chitinous exoskeletons and segmented bodies; the three types are insects, arachnids, and crustaceans. Bodies of arthropods typically come in three sections, the head, the thorax, and the abdomen. Each of these is a segment. But some species, such as a centipede or a millipede, have more segments.