My grandchildren all called me Gramma, then when the 7th one came along he named us Nana & Papa, he would not say Gramma & Grampa, then when the 8th & ninth came along they also called us Nana & Papa because they were close to the 7th. So I say, let the grandchild name you, so to speak, pick a name, but don't be surprised if the grand baby changes it. We love Nana & Papa!