Hello colleagues,
I agree that the name appears to be سسنه, which occurs very commonly as a given name among Egyptian Christians in the papyrological record, especially in documents of the tenth and eleventh centuries. Maybe someone with better Coptic (and Greek and Latin) than mine has some insight on the etymology, though Ramez's point sounds good to me. Grohmann, Arabic Papyri in the Egyptian Library vol. 1, p. 179, says the Coptic name is usually spelled ⲥⲓⲥⲓⲛⲛⲁ, ⲥⲓⲥⲓⲛⲓ, or ⲥⲓⲥⲛⲉ; Crum, Coptic Manuscripts Brought from the Fayyum, p. 55, gives Greek versions that are presumably found in papyri as well.
All best,
Lev