ductless gland vs secretor

ductless gland and secretor both are nouns.

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

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

ductless gland: any of the glands of the endocrine system that secrete hormones directly into the bloodstream
secretor: any of various organs that synthesize substances needed by the body and release it through ducts or directly into the bloodstream

Other hypernyms of ductless gland include gland, secreter, secretory organ.

ductless gland (noun)	secretor (noun)
any of the glands of the endocrine system that secrete hormones directly into the bloodstream	any of various organs that synthesize substances needed by the body and release it through ducts or directly into the bloodstream