cortex vs occipital cortex

cortex and occipital cortex both are nouns.

Word	Noun	Adjective	Verb	Adverb
cortex	Yes	No	No	No
occipital cortex	Yes	No	No	No

cortex (noun)	occipital cortex (noun)
the tissue forming the outer layer of an organ or structure in plant or animal	that part of the cerebral cortex in either hemisphere of the brain lying in the back of the head
the layer of unmyelinated neurons (the grey matter) forming the cortex of the cerebrum
the tissue that surrounds the lens nucleus