Genesis 36:39 - the grandmother of Matred (מתרד), whose daughter Meheytav-El (מהיטבל) married Hadar (הדר), an Edomite king.
Gesenius insists that it was a man's name, but this is untenable, even without the overt statement in the Genesis reference that she was female.
Mey (מי) means "waters of", and Zahav (זהב) is gold, surely an allusion to the sun's rays rather than a comment on the waters of a spring or fountain, either way sacred to the sun-god.
Similar names occur in the Tanach, as: Mey Ha Yarkon (מי הירקון), a town in the territory of Dan, named after a nearby spring or fountain (Joshua 19:46); Mey Nephto'ach (מי נפתוח), a fountain in the tribe of Yehudah, near the valley of Ben-Hinnom outside Yeru-Shalayim (Joshua 15:9, 18:15); Mey Dev'a (מידבא), a town in the territory of Re'u-Ven (Isaiah 15:2 places it in Mo-Av, close to Mount Nevo, but this is not a problem as Re'u-Ven disappeared early on, conquered by the people who became the Beney Mo-Av).
Similar names occur in the Tanach, as: Mey Ha Yarkon (מי הירקון), a town in the territory of Dan, named after a nearby spring or fountain (Joshua 19:46); Mey Nephto'ach (מי נפתוח), a fountain in the tribe of Yehudah, near the valley of Ben-Hinnom outside Yeru-Shalayim (Joshua 15:9, 18:15); Mey Dev'a (מידבא), a town in the territory of Re'u-Ven (Isaiah 15:2 places it in Mo-Av, close to Mount Nevo, but this is not a problem as Re'u-Ven disappeared early on, conquered by the people who became the Beney Mo-Av).