Where does “στειρώνω” come from?

στειρώνω (Greek) comes from Koine Greek στειρόω, from Ancient Greek στεῖρος, from Proto-Hellenic steřřos, from Proto-Indo-European ster-yos, from Proto-Indo-European ster- — sterile, infertile.

στειρώνω (Greek): neuter, sterilize, spay