Where does “ek-” come from?

ek- (Ido) comes from Ido ek, from Ancient Greek ἐκ, from Proto-Hellenic *eks.

Definitions

Step	Language	Word	Meaning
1	Ido	ek	out; out, out of, out from, from; of, made from,...
2	Ancient Greek	ἐκ	Out of, from; from, with the source of; to denote...
3	Proto-Hellenic	*eks	—