central nervous system vs pyramidal tract

central nervous system and pyramidal tract both are nouns.

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

central nervous system (noun)	pyramidal 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