My beloved maternal grandmother was "Granny". She, along with her mother, my sweet "Mammaw", taught me to sew. My maternal grandfather was "Papaw" or "Pop". He was a tall, stern-looking man who had a heart of gold underneath! I miss all three of them very much. <3
My paternal grandparents were "Mammaw" and "Papaw", but there was some sort of disagreement with my parents when I was about 5 years old, and they broke off all contact with us, even me and my sister, who was an infant at the time. I didn't really know them, but from what little I remember, maybe it's just as well.
DH and I don't have children, but my sister's son (my nephew) calls my mother "Nanny", and my father "Papaw". My mother-in-law is "Granny".