Where does “Jayhoun” come from?

Jayhoun (English) comes from Arabic جَيْحُون, from Biblical Hebrew גִּיחוֹן.

Ancestry of “Jayhoun”, step by step

Step	Language	Word	Meaning
1	Arabic	جَيْحُون	Amu Darya; Gihon
2	Biblical Hebrew	גִּיחוֹן	—

Jayhoun — Etymology, Origin & Word History | Etymology Explorer