sweat duct vs ductulus

sweat duct and ductulus both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweat duct	Yes	No	No	No
ductulus	Yes	No	No	No

As nouns, ductulus is a hypernym of sweat duct; that is, ductulus is a word with a broader meaning than sweat duct:

sweat duct: a small duct that conveys sweat from a sudoriferous gland to the surface of the skin
ductulus: a very small duct

Other hypernyms of sweat duct include ductule.

sweat duct (noun)	ductulus (noun)
a small duct that conveys sweat from a sudoriferous gland to the surface of the skin	a very small duct