epididymis vs duct

epididymis and duct both are nouns.

Word	Noun	Adjective	Verb	Adverb
epididymis	Yes	No	No	No
duct	Yes	No	No	No

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

epididymis: a convoluted tubule in each testis; carries sperm to vas deferens
duct: a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance

Other hypernyms of epididymis include canal, channel, epithelial duct.

epididymis (noun)	duct (noun)
a convoluted tubule in each testis; carries sperm to vas deferens	an enclosed conduit for a fluid
	a bodily passage or tube lined with epithelial cells and conveying a secretion or other substance
	a continuous tube formed by a row of elongated cells lacking intervening end walls