My DH's dad remarried a few years ago and while the lady he married is fine, I don't really know very well her and she's only been in our lives for a short time. My DD was born 7 months ago and DH's dad's wife keeps insisting on being called "nanny" and refers to my DD as her granddaughter. I have really, really strong feelings about who should be called gran or nanny, as I had a really strong relationship with my gran before she died and I believe that grandmother is a title which has to be earned by hard work, bringing up the parents of the child. I know I'm probably being petty, but how do I explain to her that I don't want her being "nanny"?