Where does “συνημίτονο” come from?

συνημίτονο (Greek) comes from Greek συν-, from Ancient Greek σῠν-, from Ancient Greek σύν, from Proto-Hellenic *ksún — beside, with.

συνημίτονο (Greek): cosine

Definitions

Step	Language	Word	Meaning
1	Greek	συν-	with, together, co-, syn-; indicates...
2	Ancient Greek	σῠν-	together; with, together
3	Ancient Greek	σύν	beside, with
4	Proto-Hellenic	*ksún	beside, with