sweat duct vs ductule

sweat duct and ductule both are nouns.

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

As nouns, ductule is a hypernym of sweat duct; that is, ductule 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
ductule: a very small duct

Other hypernyms of sweat duct include ductulus.

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