Just came across the name "Gisha" as a Hebrew name. Although I'm skeptical
Lanie BergmanDear Lanie.
"My logic" says: Gisha / Hisha, nicknames for Gilda / Hilda.
I don't know of such Hebrew name, but I suppose that if it's not nickname
than it might be in Yiddish (but that is for another fellow to answer).
Regards. Udi Cain.