An exoskeleton was an external skeleton used in place of internal bones and was an anatomical feature of many sentient and non-sentient species, particularly insectoid species. Exoskeletons were usually comprised of chitin and could be quite durable. Such notable species that possessed exoskeletons included the Gand, the Alkari, the Arachnids, the Gaim, certain Zerg and Xenomorph types, the Geonosians, the Givin, the Kamarians, and the Verpine.
An exoskeleton was also a large suit of armor designed to augment its wearer's strength. Often it had weapons built into it. Exoskeletons included some of the ones from the Vuy'ti universe.
Other examples included the LS209 Exoskeleton.