Where does “بَاشْ” come from?

بَاشْ (Old Anatolian Turkish) comes from Proto-Turkic baĺč — head; beginning.

Ancestry of “بَاشْ”, step by step

Step	Language	Word	Meaning
1	Proto-Turkic	baĺč	head; beginning

بَاشْ — Etymology, Origin & Word History | Etymology Explorer