adrenal gland vs ductless gland

adrenal gland and ductless gland both are nouns.

Word	Noun	Adjective	Verb	Adverb
adrenal gland	Yes	No	No	No
ductless gland	Yes	No	No	No

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

adrenal gland: either of a pair of complex endocrine glands situated near the kidney
ductless gland: any of the glands of the endocrine system that secrete hormones directly into the bloodstream

Other hypernyms of adrenal gland include endocrine, endocrine gland.

adrenal gland (noun)	ductless gland (noun)
either of a pair of complex endocrine glands situated near the kidney	any of the glands of the endocrine system that secrete hormones directly into the bloodstream