aculeus vs thorn

aculeus and thorn both are nouns.

Word	Noun	Adjective	Verb	Adverb
aculeus	Yes	No	No	No
thorn	Yes	No	No	No

As nouns, thorn is a hyponym of aculeus; that is, thorn is a word with a more specific, narrower meaning than aculeus:

Other hyponyms of aculeus include pricker, prickle, spikelet, spine, sticker.

aculeus (noun)	thorn (noun)
a sharp-pointed process especially a sting of a hymenopterous insect	something that causes irritation and annoyance
a stiff sharp-pointed plant process	a Germanic character of runic origin
	a small sharp-pointed tip resembling a spike on a stem or leaf