Gramma and Grampa, just like the bio kids do.
My stepkids call my mother Mama D____, which is funny because they call DH's mom just K__ and their mothers mom Grandma V__, like a woman who has no biological connection to them at all is closer to being Mama than their own grandparents.
My SS calls my parents by their first names. We married when he was 6 and that is what was comfortable for him.
Grandma and Grandpa. He also calls dh's stepdad "Grandpa" and his mom's stepdad "Grandpa." My mom was a stepmom, too, so my halfsibs kids call her grandma, too. On our wedding day, my parents took him aside and gave him a teddy bear and told him they were so excited to be getting a new grandson. He was really thrilled. I still remember him running around that day with his teddy bear telling everyone he had new grandparents.
He was 4. I can see if he'd been the first grandchild I
might have felt awkward to suddenly start refering to my parents as "grandma" and "grandpa."
(Background: Cora was conceived with someone else, but my first husband, B, was the one in her life from about a month prior to her birth, so he adopted her after we got maried.)
With B it was really simple, and kinda funny. When we got engaged, Cora was 2. She already knew B's parents really well, and we had even spent Christmas eve night and Christmas morning there (Santa came there.) They were so happy when we got engaged to be getting her as a granddaughter, that I'm not sure we had finished telling them we were engaged before they told her to call them Grandma and Grandpa!
So the next question was how to differentiate between the grandparents. Just Grandma FirstName and Grandma FirstName was fine, and Grandpa FirstName works for my dad, but my stepdad and B's dad have the same name! (My mom and stepdad lived very close to us, as did B's parents, so she saw them all at least once a week). I didn't like Pop-pop, which my stepdad wanted. So while we were kind of playing it by ear while trying to figure out an answer, Cora figured it out for us. You see, my stepdad is a pretty formal (read:anal) guy. He always wears a suit and tie, like at least six days a week, even though he worked at home, part-time, and even if he didn't leave the house. And B's dad is and was a very laid back retiree. So she started calling them "Grandpa FirstName with a tie" and "Grandpa FirstName without a tie"!!!
my kids call thier step-grandparents grandma a pop-pop, since that is what my stepchildren (thier bio-grandchildren) were calling them. Since all the children were pretty young, all under 5 when DH and I met, this was the easiest way of going about it.
My SD just suggested calling my mom Grandma Firstname Alive. (Her late paternal grandmother has the same first name as my mother, as I stated upthread.)
This will not work. (Thankfully, it cracked my SO up rather than depressed him. It still is not a good idea.)
My boyfriend and I just went through this whole name deciding thing with my parents actually, for his daughter.
At first he was really possesive about it and didn't feel comfortable having her call them Grammy & Pappy or any for thereof...
I kept talking to him about it and laid it out as such... he said himself that he wanted my parents to be a part of his daughter's life. She is only three, so they will be around for most of her life... We plan on having children together, and I want all children to call them the same thing. I don't want the family to start off divided with one child calling them by their first names, and the other children calling them Grammy and such.
I had a long talk with my BF's Mom too, as her and I are close, and her family is a blended family, so I figured she could offer some insight. She agreed with me that my parents deserved grandparent names as they are already acting as grandparents (play with her, buy her things, all the grandparent-y things of spoiling, basically having a ball with it as this is the first grandchild in their lives, and my Mom has been wanting grandkids for sooo long). Her point was, either we are becoming a WHOLE family or we aren't... and the most healthy is to be a whole family and to stop sperating everything out... especially since Alex is so young and this is the family she will know for the majority of her life.
She talked to her son, and he came to the conclusion to ask my parents what they would be comfortable with her calling them. My parents were thrilled when I asked them, and without hesitation gave their answers! My Mom has always wanted to be Grammy... and to help differentiate (as both Alex's Mom's Mom and her Dad's Mom are Grammy), we tacked on the last name, Grammy Smith. My Dad said right away Poppy, which is not taken by anyone yet, so that works too.
So...talking to the grandparents about what name they would like is a good idea too.