Where does “onycho-” come from?

onycho- (English) comes from Ancient Greek ὄνυξ, from Proto-Indo-European h₃nogʰ- — claw, nail; nail.

onycho- (English): nail

Definitions

Step	Language	Word	Meaning
1	Ancient Greek	ὄνυξ	claw, nail, hoof, talon; Anything which resembles...
2	Proto-Indo-European	h₃nogʰ-	claw, nail; nail

onycho- — Etymology, Origin & Word History | Etymology Explorer