Good question. I guess first name or nickname is most likely.
Comment on How do children address a non-binary parent?
JackGreenEarth@lemm.ee 5 days ago
Tata instead of mama or papa? But also, what about parent’s siblings, or sibling’s children?
clay_pidgin@sh.itjust.works 5 days ago
meco03211@lemmy.world 5 days ago
Nephew/ niece is nibling. Like sibling.
chickenf622@sh.itjust.works 4 days ago
In that same vein I’ve seen pibling for aunt/uncle.