toenail vs onyxis

toenail and onyxis both are nouns.

Word	Noun	Adjective	Verb	Adverb
toenail	Yes	No	Yes	No
onyxis	Yes	No	No	No

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

toenail: the nail at the end of a toe
onyxis: toenail having its free tip or edges embedded in the surrounding flesh

Other hyponyms of toenail include ingrown toenail.

toenail (noun)	onyxis (noun)
the nail at the end of a toe	toenail having its free tip or edges embedded in the surrounding flesh

toenail (verb)	onyxis (verb)
drive obliquely