pricker vs aculeus

pricker and aculeus both are nouns.

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

As nouns, aculeus is a hypernym of pricker; that is, aculeus is a word with a broader meaning than pricker:

pricker (noun)	aculeus (noun)
an awl for making small holes for brads or small screws	a sharp-pointed process especially a sting of a hymenopterous insect
a small sharp-pointed tip resembling a spike on a stem or leaf	a stiff sharp-pointed plant process