posterior pituitary vs pituitary

posterior pituitary and pituitary both are nouns.

Word	Noun	Adjective	Verb	Adverb
posterior pituitary	Yes	No	No	No
pituitary	Yes	Yes	No	No

posterior pituitary (noun)	pituitary (noun)
the posterior lobe of the pituitary body; primarily glandular in nature	the master gland of the endocrine system; located at the base of the brain

posterior pituitary (adjective)	pituitary (adjective)
	of or relating to the pituitary gland