Lucky you to have this "worry"--I can't wait to have a grandchild. I hope to be called Nanny. My mom's mom was Nanny, her father was Poppa though he referred to himself as Pappy. My dad's mom started as Bobodan (don't know how) but about 7 years later, she changed to Grandma. Her husband was grandpa. My daughter has/had my mom (nanny) which she often shortened to Nan. My stepdad was Bobby (my mom's name for him), my dad was Grandpa (sometimes Gampa), my stepmother was Grandma, my MIL was Abuela, FIL was Abuelo (ex is Puerto Rican). When ex remarried, DD was older so uses first names for her stepmother's parents. Whew. Now, my DD calls my DH's father "abesan," a name I started and he loves as he loves all things Japanese and his name is Abe.