My DH family has so many nicknames for the grandmas. Mimi is what all the grandkids call his mom. He called both of his grandmothers Bing. Apparently the oldest sibling started it. He couldn't pronounce grandma but how he came up with Bing is beyond me. Eons ago my boss was Dutch and when he brought his mother over to visit, everyone called her Oma. For the longest time I thought that was actually her name. It wasn't until much later I learned it was dutch for grandma. I always liked Oma both the person and the term.