central nervous system vs corticospinal tract

central nervous system and corticospinal tract both are nouns.

Word	Noun	Adjective	Verb	Adverb
central nervous system	Yes	No	No	No
corticospinal tract	Yes	No	No	No

central nervous system (noun)	corticospinal tract (noun)
the portion of the vertebrate nervous system consisting of the brain and spinal cord	any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord