Where does “синтаксис” come from?

синтаксис (Bulgarian) comes from Russian си́нтаксис, from Ancient Greek σύνταξις, from Ancient Greek συντάσσω, from Ancient Greek σῠν-, from Ancient Greek σύν, from Proto-Hellenic *ksún — beside, with.

синтаксис (Bulgarian): syntax

Definitions

syntax

Ancestry of “синтаксис”, step by step

Step	Language	Word	Meaning
1	Russian	си́нтаксис	syntax
2	Ancient Greek	σύνταξις	an arranging, putting in order; array,...
3	Ancient Greek	συντάσσω	arrange together”, “to order
4	Ancient Greek	σῠν-	together; with, together
5	Ancient Greek	σύν	beside, with
6	Proto-Hellenic	*ksún	beside, with

Every word from Proto-Hellenic *ksún →Every word from Ancient Greek σῠν- →Every word from Ancient Greek σύν →