pars anterior vs ductless gland

pars anterior and ductless gland both are nouns.

Word	Noun	Adjective	Verb	Adverb
pars anterior	Yes	No	No	No
ductless gland	Yes	No	No	No

As nouns, ductless gland is a hypernym of pars anterior; that is, ductless gland is a word with a broader meaning than pars anterior:

pars anterior: the anterior part of the anterior pituitary
ductless gland: any of the glands of the endocrine system that secrete hormones directly into the bloodstream

Other hypernyms of pars anterior include endocrine, endocrine gland.

pars anterior (noun)	ductless gland (noun)
the anterior part of the anterior pituitary	any of the glands of the endocrine system that secrete hormones directly into the bloodstream