Cissy:

[perth tiger]

my great aunt cissy was the oldest child. her real name was matilda racheal after her 2 grandmothers, she hated the name apparently and i didnt find out about it till a long time after her death.
next time i speak to her sister i'll see if she knows why she picked cissy

[Iain...]

Thanks everyone !  Summing up..., looks as if it’s a pet-name for just about everyone !