Where does “Kahn” come from?

Kahn comes from Hebrew כהן, meaning priest.

Ancestry of “Kahn”, step by step

Step	Language	Word	Meaning
1	English	Cohen	—
2	Hebrew	כהן	defective spelling of כוהן; defective spelling of...
3	Hebrew	כוהן	A Jewish priest, a cohen or kohen: a patrilineal...