ductulus vs epithelial duct

ductulus and epithelial duct both are nouns.

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

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

ductulus: a very small duct
epithelial duct: a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance

Other hypernyms of ductulus include canal, channel, duct.

ductulus (noun)	epithelial duct (noun)
a very small duct	a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance