Where does “ὀξεῖαι” come from?

ὀξεῖαι (Ancient Greek) comes from Ancient Greek ὀξεῖα, from Ancient Greek ὀξύς, from Proto-Indo-European h₂eḱ- — sharp.

ὀξεῖαι (Ancient Greek): nominative feminine plural of ὀξῠ́ς; vocative...