My oldest called her grandma "MeeMee". Came out of the blue one day, and was all she was called, til the cancer took her.
My youngest niece had a hand in naming my oldest. Little Andi used to call me "Kavey". My daughter's name is Kathryn Victoria, KV. Thus my oldest is named after me. I call her Kavebaby, Kavegirl, Kavechild, her Uncle Gary (Uncle GaGa) calls her Kaveprincess.
Nicknames are a big thing in my family, if we like you, you get one. Like my 80 year old friend, and drywall wizard, Donkaboom Jim Davis, who took a fall from some scaffold and got a "Donkaboom". My wife is the Kavebear. She's exactly the opposite of a morning person, and her hibernation should not be interrupted. My mother was known by Amazon, and while she passed before my daughter was born, she is now Gramazon.
It doesn't hurt that I'm from a family of truckers and bikers, so everyone had a handle. Before I was Kaveman, the Wandering Wizard of the Mogollon, I was simply "Dude"
For those wondering, Mogollon is pronounced Moe-Ghee-On. Like the name, the clarified butter, and the opposite of "off".
The first settlers of the "valley of the sun" reworked the irrigation canal system the ancient Mogollon had left centuries before, giving rise to the name of our capitol city, Phoenix, as it had risen from its own ashes.