Chordata is the phylum of animals that have a number of features in
common, but most notably a notochord (which is called a spinal cord
in humans because we have a backbone, a spine, through which it is
routed). All the vertebrates (animals with a backbone) are grouped
within this phylum. The chordates also include a number of other
animals that do not have a backbone, but do have the notochord.