Where does “ἴσχο-” come from?

ἴσχο- (Ancient Greek) comes from Ancient Greek ἴσχω, from Proto-Indo-European si-sǵʰ-, from Proto-Indo-European seǵʰ- — to hold; to overpower.

Ancestry of “ἴσχο-”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	ἴσχω	hold back, restrain; stay, stop; hold fast; keep,...
2	Proto-Indo-European	si-sǵʰ-	—
3	Proto-Indo-European	seǵʰ-	to hold; to overpower

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