aculeus vs spikelet

aculeus and spikelet both are nouns.

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

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

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

aculeus (noun)	spikelet (noun)
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