Where does “ókris” come from?

ókris (Proto-Hellenic) comes from Proto-Indo-European h₂óḱris, from Proto-Indo-European h₂eḱ- — sharp.

Ancestry of “ókris”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₂óḱris	top, protrusion; sharp edge, corner
2	Proto-Indo-European	h₂eḱ-	sharp

ókris — Etymology, Origin & Word History | Etymology Explorer