I always thought "papa" referred to father. It certainly doesn't mean "grandfather". "pa" also means "father". Fro grandfather: grandpa; granddad. (I didn't know about "pop")

It isn't necessary to try to memorize different words for "grandmother" or "grandfather". If someone says that this is what they call one of their grandparents, you should believe them (unless it's derogatory). I only have nicknames for my grandmothers. I call my mom's mom "little grandma" (because she's shorter than my other grandma), and I call my dad's mom - "big grandma". I've also called her "mamaw" because my cousin got me into the habit of it. Other words for grandparents I've heard include: "paw-paw" (grandfather), "me-maw" (grandmother), "nee-nee" (grandfather), & "gran"/"gran-gran" (grandfather).

Papa usually refers to a father, but mainly in European countries. Other names for grandfather: grandpappa, pa, grandpa, gramps, pop, poppy, opa [Dutch and German] Names for grandmother: grandma, nan, nanny, oma [ Dutch/German] Of course some children devise their own names for their grandparents.

There are many variations of 'grandpa' ,'papa' could be one of them. Also 'pop', 'poppy' , 'granddad' etc... "Papa" is usually used with "Nana" ,"Nana and Papa".

I grew up calling my grandpa 'Papa Milt'